All that is needed to play fish skin riqqs in most any variety of humidity levels is a good heating pad and two riqqs. If humidity is a problem, both are left to warm together before playing and then one remains on the heating pad while you play the other, changing when needed - making sure that the skin side is not left with the heating pad on the high setting for too long in anything but the most humid situations or it will shorten the life of the skin (usually keeping the heating pad on medium is fine unless it's really humid). And if your riqq is no longer keeping a good tension even when warmed, or you live and play in a very humid location(s) - reheading will do the trick. (And reheading a fish skin riqq is actually not very difficult.)
Of course, it is always good to have a back-up riqq for severe conditions. Personally, I have an adjustable, fish skin, Cooperman riqq (which I put heavier cymbals on) when extreme outdoor humidity demands, but have only had to use it in the most humid situations, or when performing at an all day event where electricity may not be available (renaissance faires, etc).
Any instrument is "easier" and "less trouble" if made in plastic, but the sound suffers tremendously - no matter how well tuned or well made. Just as most instrumentalists would never think to switch from their beautiful sounding traditional wooden instruments to a plastic version just because they are cheaper, more stable in changing weather conditions and therefore easier to keep in tune - for me, it's the same with the traditional fish skin riqqs.
I do understand that many people aren't able to go to Egypt (or have an instructor to buy riqqs for them), and that they have access to limited choices via the Internet; I understand that the stability and simplicity not to mention price and availability make plastic headed riqqs great for beginners, and those starting out, and are also a necessity for the professional on occasion. But to my ears no matter how well played, plastic never approaches anything like the rich sound of fish and wood. Of course, everyone is entitled to their own opinion, and understandably has their own needs and requirements.
In closing, I'll simply quote the words of Master Adel Shams El Din on the subject of traditional fish skin riqqs which he has used exclusively his entire career:
"The soul of the instrument is its sound; and that sound creates the soul of the music."
How to rehead a fish skin riqq
Really, I'm doing them now (Dec 2014) so there will be a full detailed description, how to, with pictures of every step in the process very soon! I promise!