most people say 36 tooth is best compromise. I have a 32 tooth sprocket.
I can get it to go from a slow 5th gear pedaling start, without pedaling. I mean after i am moving like 3mph, dump the clutch and she will get going without pedaling.
But i have found that pedaling until the engine hits its first smooth power band its best thing to do. 32 runs ragged at low speed, it makes me go faster than I want to on the sidewalks as there is little low end smoothness.
Dude!!! if you wheels are all ossilating, then I would not be concerned with top speed at all LOL! Don't even try to go full speed until you have your rims trued!!! Then as I found out here, go fast you'll need better brakes!!! I have a 90mm Sturmey Archer on the way. There are sooo many stop and go street crossings where I live, that I doubt the stock brakes would last a month!!
I learned after riding around for awhile, to let off the gas farther out from where I was going to stop, letting the gears slow me down, then hit brakes.
Going fast is not the problem. It's stopping after gettin goin fast that's a hassle. If you have a big rural area you can haul ass on then don't worry so much about the brakes.
Inner city, get good brakes!!