i require all bands to have demo's
and urge them to have bpm's, if they dont, i tap out their demo's
i dont mess around with tempo, its super super super super super important to have the right tempo for a song.
after that, i have the smartest person in the band sit next to the next smartest person in the band and make the scratch tracks with me. this requires smart people

if you dont, you'll end up with a short verse or something retarded will be missing. i repeat, WILL be missing.
then when it comes time to track drums, its just ME and the DRUMMER. no worrying about having a buntch of other people come in on time, possibly fuck up the drummer, get bored of playing the same thing over and over, bitch and complain blah blah. the scratches are already there, the drummer just jams to them with the click on.
i tend to make very complete scratch tracks (every single part is recorded, and in stereo). its worth the effort when you do a few albums and go, oh if i had known this part was going to be here, i would have had the drummer do this instead.