i have recently brought the one from gardiners as you can attach it to the solenoid auto shut off it works really well however its max pressure is 80-85 psi. but if you could get away with that then i would recommend it, my lock up tap pressure is about 22 psi to begin with.
I would add that originally i was getting about 90 psi from the booster pump (that was the reading i was getting from an inline pressure gauge fitted after 2 pre-filters) but due to my poor input tds i need to have a bigger pure to waste ratio currently 65/35 which is what dropped it down to about 80psi, i originally had it at about 55/45 which kept it at about 90psi
the float valve i use is also the one from gardiners.
hope that makes sense
paul