This post caught my eye -- I just installed a new tank, pressure switch etc last week...........
I always use Square D pressure switches, because you can adjust them as far as your tank can handle to minimize pump cycling. The crap chinese ones at Home Depot only have one adjusting screw -- these have 2. Not only did I get a tank that is at least double the size of the old one, but I have the switch set to 28/70 ( was shooting for 30, but over adjusted & just left it that way ). It's a 30/50 switch -- right in the middle so you can have a wide range of pressures. I have 30 psi in the tank.
I had the old tank set at those pressures -- it was a tiny little tank, but I got long draw time off it.
The new tank is that much better -- pump used to kick on 3 times per shower......now only once, if that.