The first few days in Australia, I was surprised how tough hang gliding was. The glider was really hard to steer and I originally thought that was caused by the turbulent air and the lack of flying in the past 3 months.
It took me a while to realize the heat was causing it. Our sails shrink with increasing temperatures, so you have to decrease the batten length (it took about 3 turns on my inner battens and 1 or 2 on the outer to cover the 20 degree difference between last setup in Belgium and here). As important is what happens along the wing span. The Combat has rings (shims) which can be used to extend the leading edge. Mine was delivered with 4,5 mm rings. That's quite a lot, but when my glider was test-flown in January, temperatures were -30 in the Ukraine. That's 70 degrees difference to the 40 degrees we've got here. The result is that my glider became very slow in roll control because of the high lateral tension in the hot temperatures we experience here.
I made a drastic change and removed the 4,5 mm rings. The glider now has a surprisingly light handling, but bar pressure on fast glider has also increased significantly. Too much of a change. Luckily Paris went from 3 to 2 mm on his Combat and I'll be able to use his 3 mm rings on mine. I think that will provide a nice compromise.
So, anybody who's having a different glider between summer and winter: think about adding/removing rings to the leading edge. It does make a difference.