Electronic Manuals and Where to Put Pressure Gauge

[fpdiver]

Question 1: Has anyone tried this downloadable manual? Any good?

http://www.boatmanuals.info/?gclid=CMXdtrbKipsCFQ3yDAodjBqCpA


Question 2: Where am I better off putting a water pressure gauge. #1 (right)is my fresh water flush tube. #2 (left) is the pee hole tube. Motor is a 125HP, 2-stroke, Carb, 2003. Finally...15psi or 30psi gauge?

thanks