65 Psi is a little high, should work though ( I would probably want it in the 40 psi area). If you're looking for more pressure/flow at the shower you might want to start there. The shower valves/shower heads have flow restrictors in them to conserve water, especially since you're probably dealing with an 11 gal hot water heater. Try replacing the shower head with a household model and see if that helps(these also sometimes have some type of flow restrictor that might need to be removed/drilled out or played with). I did this with both the shower in the head and the cockpit and got improved results.