I just purchased a ground blind this year and was in a similiar situation about a month ago. I looked at all the seats available on the popular sites and they all seemed to have a sagging bottom and/or no back rest. I have some back problems so something with some support was important. After a few purchases and returns, the best option I found was just a simple folding chair. I found a black one for $12 and it is the perfect height and I have sat in folding chairs for long periods of times before, so I think it will work great.