It shouldn't make any difference either way on PS4. Same model PS4's?

That's a possibility. A few of my friends run Demon's Souls, and they typically start their streams with a full-on no-reset run since the game loads faster on second playthroughs in one sitting (the board goes by IGT, so it's merely a matter of convenience to grind with the shorter loads). But there's no IGT for this game (I mean maybe there is on the savefile? But is that something we want to use?), so we best figure this out.

It would have to be done manually, combing through VOD's. Some games do that but I'm really not interested in that for Infamous.