Thanks to member Talonst, I got a stock seat to experiment with. Got some Seadek foam boat deck material, made one small piece (that I forgot to photograph) and a second larger piece. Used a grinder to feather the edges on both pieces, for a smooth transition. Wanted to level the seat more, I always feel like I'm sliding forward into the tank. I'll hit Harbor Freight tomorrow and pick up some ½ x ¼ staples (for my HF air stapler), hand fit looks like stock cover will still work. I'll report how it goes