Hi Steve
Pretty sure the pumps have 20 amp fuse required stamped on them. they can draw about 8-9 amp so 10 was just too close. you don't want to be changing these in flight.
stick with the regulator you got. in practice you wont be using both pumps unless one fails so the 10 psi increase wont happen in flight. the regulator has to flow the most when the engine is stopped but pump on. I'd doubt you'd see same increase at full rpm. A bigger regulator may not be a total fix it either, would need large fuel lines also to flow 2 pumps worth of fuel.
I think just a switch on the panel is fine for activating the pumps, a pressure switch is just something else to fail. and you may not realise you've got a bad pump. it would have to be setup to switch pumps and send you an alert, all of which can be done manually without much stress.