Keeping your seat area from accululating water is easy enough. Put a little clear packing tape on the bottom of your hull covering most of the forward part of the scupper area like this:
Crack your scuppers open so that some water can move in and out.
As long as you're moving forward, water passing over the tape will scavenge your scupper and clear your seat of any standing water. You may still get a wet butt, but you're not sitting in a puddle! The tape has no problem sticking to your hull when wet, once installed.