sounds like a thorough plan...
Speaking of gas tanks.
I was trying to mount my motor on a schwinn 24" sissy bike. I did in the end but I was playing H*** getting the gas tank to mount. I wanted to use the frame as it was but the tank was too big. I took a look at a couple of smaller plastic tanks from trimmer ect. I even bought two of them. In the end I made a fake bar across the top from a sacraficial broom handle. turned out okay
One thing I would have liked about the plastic tank, I could have seen the amount of gas left in the tank. Without a gas gauge I have already run out of gas once and I have used the bike only twice. I can tell this is going to be a problem with me.