I want 2" of urethane foam under my hips, just like my living room couch. I can't buy that, and the foam in cans I can buy @ HD is too hard. So far the best I've found is wrapping the meagher leather seat with battery packing foam & shipping tape, but it wears rips in the tie string holes and comes off too easily. At least the meagher seat rocks from side to side as I pedal. Somebody gave me a seat from a Workman industrial cycle, but the nose was too wide to fit between my legs.
Picked up some garbage sofa cushions & tried to grind a well in it for the seat contour with a rotary wire brush. Ripped the edges off too easily, I can't control that process. Had a leather purse cut down to wrap around it with lacing and everything.