Rigging a transom mount water pickup?

[CharlieN]

I tapped into the lower on the opposite side where the -10 hose enters and run a gauge that reads both vacuum and pressure.
I see a low amount of vacuum at a cruise around 40mph but have not taken the effort to look at this gauge at top speed. The gauge is visually blocked by the steering and the waters I generally run are congested. With my current top speed of a bit over 60 I am curious if those that talk of high water pressures from these pickups just see it at much higher speeds.

Or might it be the location of the pickup at the inner port strake is not getting a clean flow to it?
The WP in the powerhead drops to 0 at a 900 rpm idle starts rising by 1500 and runs 20-25 soon above that.