Paul G, I can only imagine being as organized as your band. My five-piece group gets together once a week, and often there will only be four of us there. Currently, we are having some arguments about how structured we should be: we are primarily a Blues band that specializes in extended guitar and harp jams, and we really enjoy the spontaneity and improvisation of that style. It is, however, quite easy to let this improvisation turn into aimless wandering when playing in front of an audience.
We also have a wide age disparity in our band, from 28 to 53 years old (the two guitar players), so tastes and stylings tend to be quite diverse: Pretty Woman was done by Roy Orbison and Van Halen, and we do both versions simultaneously.
We spend about 1/3 of our practice working on new stuff, about 1/3 tightening up old stuff, and about 1/3 talking about band business, practicing harmonies, etc. I think Paul's tape idea is a great one for original material, and I'm going to suggest it to the group.
LEJ