I have an older doughnut-style float tube. It's got d-rings on the bottom. I've got some backpack straps for it but...it sucks. Between the bottom of the tube hitting me and the strap comfort level, I'm looking for other options. And of course the other challenge packing a tube in is other items if they can't be tucked into the tube--(fins, fish finder, etc.). So, I'm looking into other options. I've considered trying to modify an external frame backpack. But I'm also not opposed to a different tube. The newer u-shapes and platforms that could have me sitting outside the water are appealing. So what do you use? How well does it work?