Buy a new cylinder. Accept the fact that they are never round, and the plating is atrocious.
Take the new cylinder, de-grease it. Put it in your oven, and cycle it to 300 degrees a few times. Let it cool to room temp each time. Do any porting or clean-up it needs before the next step.
Then, put it in a box, add $230.00 and a new piston (for fitting) & ship it to:
They will bore it back to straight, then Nikasil plate it & hone it to size for the supplied piston.
Nikasil works. Porsche still uses it in aluminum cylinders.
I have sleeved 2 stroke engines. It is a huge pain in the backside. Making all of the transfer ports line up right, getting the sleeve pressed in to the right spot, finish machine work... Then you still need a good bore & hone to straighten up the bore after you get it assembled.
230 bucks is a bargain. If it is within .010 of round after heat cycling, they will only charge $198 if they don't have to bore it.
Just my two cents, based on experience.