New build frame up

Ok, i have a project, ive been doing motored biking for a while and been doing it the fast cheap amd wrong way. That just a pain and its expensive and frustrating. So im going to do it right and i want some advice.

Heres what i have
2005 mahattan cruisers aero delux 6 speed. (Currently a 5 speed, got it used and modded)
Astabula crank will have to be replaced for:
4 stroke HS engine and gear reduction
Sick bike parts 4 stroke shift kit
Board track style wheels from custommotoredbikes.com with 11 ga spokes with a sturmy archer 3 speed igh with drum brake, front, sturmy archer drum
Wald large dual basket rear rack
3 gal plastic marine gas tank on the rack later to be replaced with a cylindrical aluminum tank of similar capacity
Will use a dual pull lever for the brakes, will use a locking clutch lever from a previous unsuccessful build in lieu of a twist throttle
Other components will be determined as needed

So,
Who has the best HS 4 stroke motors and gear reductions and whats the deal with the G designation on the 4 stroke motors? 4g 5g 7g etc. Does this matter?
The reason im going with such a costly wheel option is multifold:
Im a heavy guy and i have had LOTS of issues with cheap trashed hubs, and broken spokes riding on the crappy roads where i live. So i opted for heavy duty wheels with the largest spokes i could find. I dont think an external gearing system would be very good with the jackshaft and i dont want to fit a new mech on the cruiser and a new shifter etc.
ALL the other HD wheels i have found with IGHs have been coaster brake set ups, which i think that i should avoid at my weight and this is the only one i have found in a wheel which isnt a coaster. The drum brakes are because they are sealed and reliable from my reaseach, and they make tire changes a bit easier in my reckoning.
Is my reasoning right here, or am i over reaching?
Thanks to anyone who replies amd gives advice.

That was informative. Not entirely the information i was looking for, but it was useful as i didnt know i needed to know that. Thats cool. Thanks.

So, i have my bike together. Went a bit of a different route than originally planned for several reasons, money amd time among them mostly.
What i ended up with:
HELIO cycles basic 4g four stroke cruiser. From helio cycles.
Its a oversized tube frame (probably a firmstrong china bike from the looks and the name on the seat)
Its a 7 speed bicycle.
12ga spokes on the rear wheel
Hub adapter fornthe motor drive
Belt drive freewheel transmission
"Custom" motor mount
Comes with "almost" everything to get the bike running out of the box with user assy required
About $1k. (Not bad, the savings from this allowed me to get all the other things i wanted for it at the same time)
It was far from perfect, but it works
The gas tank had been tested with gas before sending and there was residue which leaked out and dissolved the decal on the tank (decal wasnt a major selling point, but gas residue should be avoided in packages i think)
Seller said bike did not require a tensioner and that the bike had been assembled at the factory and tested without one and functioned. I could not achieve the same results upon assembly, so i added a spare tensioner, and got desired results. Still not a huge deal really.
Gas tank rusted within one month. Seller sent new tank. New tank had more extensive rust than original upon opening box, so discarded and bought attwood 3 gallon boat tank and assocoated plumbimg. Problem with rust solved, but the boat tank is probably going to be replaced with somethjng else soon as it isnt gravity fed and prone to air in the line that causes sputtering and dying. Kinda irksome that $1k cant get a rust free or lined tank off the bat, but im a patient guy and i just want a running bike
Kill switch wiring is shoddy but all the kits to my experience are. Will have to fix myself
Pull start broke and jammed in first two months.
Didnt get response on issue from seller, so i just ordered one. It fits and works well. Besure to remove case and pull start studs of you buy on of these and add thread locker to the motor side threads, it saves you a headache, trust me.
Most recent problem: tranmission. Bike died as if out of gas one day while riding, thoigh it was aspiration problem but when trying to restart, noticed pull start was really tight (thought motor had siezed at first) but tinkering led me to realize the back wheel was trying to turn upon starting. Didnt know exactly what that meant so i contacted the seller and he quickly (like 1 hr actually, it was fast) responded that it was a broken clutch spring and he was sending me one asap. So im waiting for that.
Seems like a lot of trouble, but more or less, I'm happy with it.
Pros, other than once, the seller was fast and helpful with problems. Hes polite and knowledgeable.
Motor runs well, starts on first pull almost always, (throttle is wonky, both the one they sent which promptly broke and the spare one i replaced it with, so i will probably replace it with a different set up altogether)
The back wheel is 12 ga spokes and and the adapter is concentric all the way. No problems there so far.
Bike is decent for a low end bike. Dont expect a custom quality build for $1k shipped, its a starter bike and a platform for expanding your hobby.
Mounting the motor is easy and the mount is sturdy, make sure to spray with rust preventative. Hardware has been good quality so far, no cammed out fasteners. Its a motor kit with motor kit componnents and some improved parts, its a good deal to start out with for $1k shipped.

To the basic bike i added:
Bright eyes 1200 lm headlight (great light)
Avantek turn signal (good light, but the mount broke)
Worksman industrial horn (skip this unless you just have to have it)
Wald dual rear basket (very good choice)
Basic tool kit and tools i had already in a tool bag
Attwood 3 gallon boat tank mentioned above
Kryptonite fagheddabodit chain and new york mini ulock
Bully pager alarm lock (a medium to high quality u lock with a tamper alarm and pager with 2k' range

Between the kryptonite chain and lock and the bully alarm lock i think the bike is pretty secure when locked up. I have an additional low end kryptonite chain and a cable i already had that i use when needed. All of the security gear fits in a small tool bag and sits in the basket on back.
I will be getting a "burner" type smart phone (ie cheap) to stash on the bike as a tracking device and back up phone at some point in the future.
Just gotta wait for the clutch spring to get it back on the road.
On that note, does anyone have suggestions for off the shelf spring i coukd stock up on in case this happens again?


Addendum:
Just to be clear, the seller, Kyle at Helio Bikes has been helpful and prompt with the exception of one time. Answering even basic questions quickly. The one time he wasnt, it was more than likely an email issue and i simply didnt try to contact a second time, i was in a hurry and needed to get the bike back up.
He sells a wide range of set ups at his website for a wide range of prices and its one of the better websites ive seen for complete bikes shipped. Its pretty likely if you are looking for something you can just take out of a couple boxes, put together and have going in a few hours, this is a good way to go.
Would the build i wanted have been better? Sure by an order of magnitude all the way around. But i was gonna end up being at least twice as much and take 3 times as long as each major component set was going to come from a different vendor or vendors. I dealt with Kyle for the basic bike and motor set up, and amazon for everything else. I ordered at the beginning of june and had everything together and running by the third week in june. I would still be waiting for parts and puttong things together the other way. This got me on the road and saving money much faster.