Those are good Qs, Howie. It'll take as long as long as it takes to sort 70+ caps.
Will I like the sound? I really can't be sure, but the engineer is positive these caps are an improvement over stock. Indeed, he doesn't recognise the one that has failed, although he seems to think it's Italian lol.
A couple of audiophiles who know they're way around a workbench have both given his ideas the thumbs up, so I'm "cautiously optimistic".
Then again, I felt similar before going on dates as a teenager, and they ended up disastrously lol.