I wear a liner sock in my Brookie Knee Highs with whatever Teva water shoe I can find at a discount ;)

I agree with OS, I think Cool-max is superior to Polypro.
I also bring a pair of Merino wool dress socks if the water is real cold for my liner sock.

The fit of your shoe is paramount for comfort and stability. I'd rather have a looser fit, and build if up with aftermarket insoles, than a tight fit that pinches and cuts circulation. Your feet swell as much as 1 whole size in a day. The also get bigger as you age and gravity takes it's toll.
I wore a size 9 1/2 D in the Army, now wear a size 10 1/2 E.

If your still having hot spot no matter what you do, here's a little tip most dedicated runners know ( I'm not one of them). Use a clear sports deodorant or special runners "lube", and run it over the area your having problems with. I use it on heels/balls feet and around the toe area. Then put on liner sock and go from there.
It will cut the friction/ perspiration and foot odor way down. You have too like that ;D