Quoted from Phat_Jay:If I remember right it’s 5/8 on legs 9/16 on head.
This is typical. I’ve sometimes seen odd size leg bolts though. I typically make sure to have a 5/8, 9/16 and 1/2 inch open end set and a flat + phillips screwdriver with me just because you never know.
Oh yeah a hex wrench as well. Doesn’t have to be pinball specific but does need to be long enough to go deep and give you good leverage... but this is only for newer games.