Not sure what "bad" ball room pattern is. I'm guessing you mean the one that i always get where it hits your right as you come out of the door. No clue about the mini, but I can say with a hard reset and no deaths, I always get the good Ridley pattern, even before I started getting half decent times. There are two hints that should give away if its bad pattern. One is the first (or at least i think its the first) squeept in norfair. It can jump 3 heights. If it jumps the highest (almost to the ceiling), then its bad pattern. Second is right outside Ridley's room. The side hopper on the ceiling can jump two heights. If it jumps further off the ceiling (down to where it'll probably hit you), then it's bad pattern. That might help you figure it out earlier anyway
I'd check yogi's tutorial, but I think it's entirely based on the cart/rom you're using and deaths since last hard reset. I THINK all carts/roms will give the good pattern before the first death of a hard reset (ie not just the reset button but a full power off/power on cycle). If you hard reset and don't die, should get the good Ridley pattern and same ballroom every time.
for me. most important part is freezing his low projectiles in a good spot where you can sort of use them as a backboard. after that, you need to hug him (to get more shots in) and as bb said, hold b and tap select and the directional. The directional tapping will get you close, but it also makes you shoot faster. AFAIK, once you hold B, hitting any button is the equivalent of hitting b again so it increases mash speed
So pressing B does not do it for me... BUT if i get a red upgrade thinking and move the pod from '?' to speed when i have exactly 10,000 points, thats when it gives me the auto fire (and in your video, you do the same).