There is a list of pause frames for Monkey Ball 2, that can be found here: http://www.speedrun.com/supermonkeyball2/guide/8bdkm

I think the best place to find pause frames for SMB1 is by watching Callumbal's runs, since a list doesn't currently exist.

Some more info for pause buffering is to make sure you're not using pause unpause to buffer. Normally this skips about 6-10 frames at a time. For 1-2 frames at a time, which is highly important for speedrunners, put the end of your thumb on the pause button, then the part of your thumb underneath your knuckle over the B button. Then pause buffer by rolling your thumb from the knuckle to the tip to quickly skip 1-2 frames at a time,

I hope this helps.

Claw grip is never a good idea unless you're playing on Xbox. You skip 1 frame at a time way less consistently, and it can often lead to hand pain or wrist problems. Also you have to readjust your right hand entirely on the controller in order to do this rather than just simply move your thumb over slightly.

Obviously you can skip different amounts of frames at a time with the technique I mentioned, you just roll your thumb from B to start slower to skip more. But seriously, claw grip is not a good idea.