Mark1234, Agreed the 2-seater trainers come down faster and are generally best kept within range of the home field. Fibreglass single seaters have minimum sink in 100-120'/min range.
800'/min is something I'm quite used to seeing in a C-172 at idle, generally with 20 flaps; about the same in a Citabria.
At 2000' in a glider, I'm starting to look for fields, especially as at that level you're generally below the working band. While all the time I'm looking for lift, I do want to have a good field in my pocket by the time I'm down to 1,500. Once I have that the name of the game is to find sufficient lift to get away before I'm down to 800' at which time I've run out of quarters and it's time for the downwind.