Hi Jim,
My recommendation is to install a couple of these valves in the floor, at the sides near the rear, where they won’t be covered by your seat. When the valves are open, the packraft is self-bailing, and when they’re closed (on flat water) it’s dryer and lighter (because you’re not hauling water in the boat).
You could also model a self-bailing system on one of the major packraft manufacturer’s designs.
Cheers!