Only when the switch says ON and OFF pressures on seperate readouts and a third for pressure at the moment, would I consider dropping 2 bills for it. that would make it very human friendly.
You are up against a Franklin pumptek for 80 to 150 bucks, a 8$ gauge and a 12$ switch with proven reliability - and some boraxo or diatomaceous earth in the switch box, or gold bond powder, keeps the bugs far away. Or a mothball - add 5 cents.
You have made a MECHANICAL device that works well, and again, a foray into that world of a dumpster filled with pumps dependant on ELECTRONIC switches that you have raved against, rather surprises me. I think your customers would prefer combination digital and mechanical device that gives at a glance the settings. If Grundfos and their gaggle of engineers cant get it right, can anyone?