I stopped in because I thought the 'hookworm' tires were cool but maybe I can help.
The thing is, once you go wider than ~2.25" tires on a direct drive 2-stroke, the chain won't fit past the tire, and trying to modify your engine mount and rear sprocket is usually an expensive futile effort.
My basic build rule is if the tires at their widest point is over 2 ¼" you need pedal side drive.
Your bicycles pedal side always works.
That is just the price of going with a 2-stroke with fat tires, but to works well.
A SickBikeParts shift kit has worked well for me anyway.
Silly to do without bicycle rear wheel gears to take advantage of having geared engine power as a bonus, but doable, and you can always lace a new internal shifting hub into your back wheel.
These Kenda Flame tires are 2.65" and the chain clears.
You can go much wider, it just a matter of tying into the pedal drive.