Re: noobie question
I change mine one at a time as per the instructions here on Jemsite. Of course, my JEM is brand new and I just changed strings for the second time this week (and finally got it right!) I don't block the trem. Just one at a time, stretch, tune, stretch, tune, you know the drill. After the process my JEM was back in tune and thankfully pretty much stays in tune - trem leveled off dead flat, no problems.
One of these days I'll give it a good clean but I wipe it down after playing and keep it pretty tidy so I don't feel the need to totally polish my fretboard at each string change.