Having spoken to a few people, it seems Thor uses a 140mm bore cylinder whilst 63mm is what a few people suggest for a flipper. I've managed to source a 125mm cylinder with a 175mm stroke for a cheaper price than it would've been to get a 80mm or 100mm so I'm going to work with that. It's rated up to 12 Bar and I intend to build for that if I can, but it's good to know 10 bar might work if needs be