My 10c worth... I'm not so sure doing a lot of rehearsal without the bass player is wise. If anything the bass player and drummer need to lock in more than the guitar player... I think our process was this, (we had a great producer take care of all the prep....) Make click track. Find drum samples to suit song (Verse Chorus etc). Have rhythm guitar play to scratch track, add scratch vocal. Remove drum track and have drummer play to that (click with rhythm and vocal). Then start proper recording of each track based on the final drum track. Getting bass in 2nd and so on. BUT.... I believe the key is to retain the feel of real people. I prefer the old school way of playing together live, not being scared of a little bleed and so on. Lead guitar, effects and whatever else added later. As far as timing goes, personally I don't feel movement of 3-4 BPMs across a song is a big deal, especially one with dynamics. Rick Beato just did a cool video, Quantizing John Bonham...I think the song was Rock and Roll or something. John Bonham wavered 3-4 BPMs across the song. Some listeners with great timing "might" have known this but it certainly didn't seem to detract from the song. More likely it added style, dynamics and groove to it instead.