What's the use to install an induction meter under the cowl. Should have installed it screwed at front cowl, there will be able to visually check idle revs along max wot rpm range achieved as loaded if plan venturing to play with different prop pitches.
Or screwed to dashboard with extended pick up cable. a matter to check with manufacturer what's the max extended cable length that can be used once routed from engine to dashboard for a exact reading.
Happy Boating