Found this off Gombergs sight for bridles. Pilot Tuning?
Lines and fabric may change after a few first flights -- like a new pair of shoes settes in with wear. For simple "field tuning", I simply gather all the lines in one hand. I adjust the bottom row until the kite is flying straight. Then adjust the top to orient for lift. Then remove the slack from any other lines.
I tie a knot in all the lines, connect a flying line, and send it up to see how the adjustment worked. If correct, I just cut off all the loose bits.
Same works for SkyForms.
Also,found some info on the trailing edge venting for high winds...check the stitching and possibly close pin shut. Essentially, making the opening smaller. Cured some other peoples issues as you described.