RE: Comfortable ground seat.
Go to a medical supply web site. Look under the "shower chair" category. You can get about any size you want, and with or without padding. They are made to get wet. Also the legs are adjustable for height. If you are on uneven ground they can be adjusted to be level on any contour ground. I am 6'5" and have no problem with heigth on the chairs I bought. Yes I said chairs-I think I have four of them. They even make them with wheels, if you feel the need. The fact that they are adjustable is what makes them so comfortable.
I am a handicapped hunter. These chairs along with my Kawasaki Mule is the one two punch that has allowed me to comfortably be able to get back out there. Tom.