As it happens, my son was married three weeks ago in Dallas, Texas. Fortunately, the wedding and reception were in a nice, cold church with attached reception room. Good thing, since it was 92 degrees (F) outside!! I survived by drinking LOTS of cold water. I also skipped wearing stockings, but that one is probably not much help to you.
I'm sorry that you have to endure either the sweating or the itching. I have noticed that if I become even slightly dehydrated, my skin, especially on my arms and back, does itch like crazy. Uping my water intake and applying skin moisturizes (like Aveeno lotion w/oatmeal) helps me. Also, my doctor recommended I cut showers to three or four short ones a week. Of course, this only works when I'm NOT in the sweating phase.
I wish you much luck in finding your own solutions, and thank you for passing along anything new you may come up with.