PBL this
TURNING FLIGHT AND SIDESLIP IN HANG GLIDERS (Summary)
appears to be a fairly detailed treatment by a hang glider pilot. I have not read it all carefully, as it goes into more detail than I as a casual sporting flyer would want to read. So far as I can tell it does address your interests, and I will be interested to see what you make of it.
It does touch upon a point that has confused me in the past. Hang glider pilots are encouraged to let the nose up a bit in turns, which always seemed a bit counter intuitive to me, given we normally fly not much above the stall.