Most commonly used pistons are JE in either stock bore with higher compression, or 1216 bigbore, cam choice is usually early GSXR750. The stock carbs will handle a 1216 kit with GSXR cams, but folks more inclined to drag strip performance will go with 2mm bigger smoothbore Mikunis. You can go larger than 1216, but its recommended to go with an aftermarket cylinder block beyond 1216. (1246 can be done with a stock block and new sleeves, but big block is better.)
1246 can be done on the Bandit with just boreing the block, which wasn't possible on the 1100 GSXR.
I have built everthing from 1186 to 1246, but I believe that the 1216 is the best way to go because it leaves you with one more size to go if you have to re-bore due to a piston problem.
Mine is a 1246 now, 13 to 1 JE pistons. For a street bike, I would go with the Holeshot pistons, 10.8 to 1, I think.
I weight 240 lbs, and run 9.78 et at 139 mph, best pass.