Another thing you will not know being new to this is that the BW prop was tHe best on the block in the 90's. Highly regarded like the Catto is now.
Van's published a comparison chart in RVator with several props and BW was the best. As I mentioned to you on FB you can probably get this re-pitched.
I will again Mage the point that you would probably not notice any difference between 7/8 an full throttle. As for the mixture arm you can drill another hole in the quadrant lever higher in its travel to gain full movement.
However, you might not need to do anything to it. If the available travel you have cuts the engine at full lean, and is rIch enough to start on a cold day you probably have all the movement you need. A fraction short either way may again not make much difference.
I would suggest that you get a good RV guy to look at it before you create yourself a lot of work.
In completion stage of Loehle P5151
Built and now Flying G.BVLR Vans RV4
Rebuilt G.BDBD Tailwind
Rebuilt G BVTN Kitfox
Built G CDCD RV9A with WAM120
Riveted wings on Glastar G.LEZZ Now (G. SKUA)