Ahhh ok. The pavement part makes more sense. Off-road, you'll definitely want less.

As for the whole gauge thing, I pump up at home with my gauge-equipped floor pump and note my starting pressure. Then I let air off as I ride until I find nirvana, and check my final pressure when I get home.

If your pump has two heads, it must be able to do both presta and schrader valves. Do you have a link or a picture?