Hi Mark,
I have IP38-98 with the toilet forward and the vanity to port. I removed the seat a long time ago because I had trouble with leaking around the bulkhead when water became trapped there. There were four screws that held the seat down, I simply plugged the holes.
We do not sit to shower and it actually makes it easier by giving a bit more room. The old seat became a support for my inverter-charger under the nav station.
Good luck,
Ed