I will also say, as someone who abhors the heat on every general basis, the cooling vest solution is a little bit of too good to be true. I'm not exactly even sure why. Mine can be rigged portable with a tiny backpack sort of like a camelbak and I still wouldn't wear it to wdw.
I always feel weird after spending a lot of time in it. My intuition is that the body will balance temp when your top half is being cooled but it's a task for which it was not designed.