One or more start cylinder may be located remote from the gliderport.
That should allow you to get out from under your class B. Remote
start cylinders are used routinely at Parowan, Uvalde and other
contest sites.

One consideration is that a site so close to class B almost certainly
means contending with power traffic. It would be better to choose a
location that is away from power traffic if possible to reduce the
collision hazard.

A good contest site needs a selection of motels and restaurants
nearby. If you are really wanting to design a first class contest
site, you should consider designing for 65 gliders not 40. That
means lots of tie-down / camping area. You would want the landing
area at least wide enough for two or three gliders to land at the same
time.

I hope it works out.