I have a stock 7.4MPI and I will be procharging it later this season. I would first like to observe normally aspirated pressures on various elevation California lakes prior to adding any boost. I only plan to apply 3-5#s of boost and therefore would only need a 45-50" pressure Gage. I don't want a boost Gage as I am interested in reading atmospheric pressure prior to engine start. I have older eyes and would like a 3-4" diameter Gage (preferably white). I will also need a fuel pressure Gage as well; but I do not know the needed range before and after procharging.

You could try an aviation manifold pressure gauge, as they are usually marked in a standard fashion. 10 to 70"hg.