put in an actual seat and not a flat piece of foam. You can still have your seat 1/2" from the bottom but instead of the fat and muscles of your backside spreading out allowing your weight to concentrate on two sit bones,,and the associated psiatic nerves what you want is an actual seat that supports the fat and muscle to LIFT your pelvis up off those nerves. Which is why kayak seats are bucket shaped and not a flat piece of foam. I made a hard glass seat for a Mariner I had that was more comfortable than any foam seat because it fit me. It's not the squish that makes a seat comfortable, it's how it supports the fat/muscle to take the weight off the sit bones. A poor fitting foam seat could be less comfortable than a hard fiberglass one that fits right. A lot of folks focus on underthigh support but that's after you've already got the back and sides dialed in.

Think of it this way,,when you're leaning your kayak 20degrees,,,what is your flat foam pad doing for support?