Bipod length

I didn't find this subject when I searched, if I missed it my apologies. I joined a club with a 100, 200, and 300 yard range, and I want to start some long range shooting (if you call 300 yds long range). I wanted to get some opinions on what is a good length for a bipod. I want to shoot off of a bench, but I'd like to try some other positions as well, including prone.
Thanks in advance!