With the gel seats,, and I know it is not the most attractive thing,, but throw a heavy towel over it,,preferably a light colored one. I have found that always keeps my set cool and if there is water available,, dampen the towel to where it stays in place and makes it even cooler when hopping on it.
I have a Mustang Seat,, the backrest is GREAT!!!!! The bottom is stiff,,, I had back aches with the factory seat, but my bottom was comfortable,,, now with the Mustang seat,, I have few back aches but my but goes numb. I have ordered a "Buttbuffer" pad in order to try to get this right.