The vacuum switch is adjustable. The pressure switch for the side of the trans is not.
If your gearing/tire size/final ratio is outside the parametrs of the switch you can get a pressure switch at NAPA for the correct pressure.
They have a wide selection, but you need a good counterguy, so dont go to McParts for it, Go to NAPA.
We used a 62 PSI switch because the 52 PSI at PTC was to Low as the rear gear was a 4.10.
The vacuum switch is good as it is throttle inclination sensitive. Meaning...at cruise(vacuum high) it holds, when the throttle is opened Vacuum is dropped and switch changes states(continuity) there are both normally open and normally closed contacts on the vacuum switch. Plus it is adjustable as well.so If you have a big cam you can tailor it to your driving habit.
Fact is stranger than Fiction