Does anyone have any save states of the 2nd loops for DDP / DOJ / Ketsui? I want to give them a try out of curiosity but I'm not good enough to get there legit
I think you'll find carrying save states across different PCs and MAME versions more difficult than just starting fresh.
The easiest thing to do would be to map the save and load state buttons to your controller and save scum the first loops in very small chunks (a couple seconds at a time), overwriting the previous save each time. You could easily do a no death/no bomb run of any of those games in an hour or less.
I thought the same, but I can at the same time imagine it's easy to accidentally save when it's already too late (certain placements contra upcoming patterns can render being walled impossible to avoid, for example). Some base knowledge would be required for it to be "easily" done within an hour I'd say.