Up to about 10mph you could get away with #90 but you would want #150 above that.
I only have an 80' set of #150 and I've found that to be a great length. Heard of some pilots using 100' and even 120'.
Wind range is going to be down to personal preference and mood. At 20mph it can get a little, ummm, hairy. Most fun on mine was in #90 x 50' in 10mph. Fly to the top of the window then pull the top lines as for a catch and throw. Then watch as it gracefully flies out to load up again. Magic.
- Dayhiker likes this