I do get the full body sweats...particularly at night...but to be honest this only started when mine spread out to my entire upper body and I didn't get it when the RSD was just in my left ankle (where it started).

I haven't noticed any difference between sleeping on different mattresses unfortunately...as I have to change positions all night long and cannot sleep/lay on my back at all because the pain is just too severe there to get comfortable. However...I have had to sleep on the couch for the past year because I cannot safely navigate the stairs all the time and since there is no bathroom upstairs in the bedroom it just isn't a good idea to sleep up there. So I honestly haven't exactly tried a lot of options.