Try adding a few big slabs of bark at like 70-80 degree angles. Of course even with good molting spots, some of them are just daredevils try it in the worst possible... but for the most part that'll help!
That's what I had before and even though the second one molted out on that, he still had messed up wings. Maybe there is just too much wing for the super dry climate here.
Another factor that might cause large winged species to dry imperfectly is overcrowding. Too much jostling for space or activity might cause them to move from their intended drying perch too soon.
I only have 12 of them in an 83L tub so I don't think that's it. Another one molted out and his wings are 95% inflated, but his color is all wrong, just like the other two.