Linhof Multi Focus Optical Finder on Crown Graphic with top rangefinder

Hi there,
I have bought 4x5 Crown Graphic and it is in good condition with coupled 135mm lens and reliable top rangefinder.
However its viewfinder feels plasticky and not precise. I had an idea to buy Linhof Multi Focus Optical Finder or similar equivalent and stack it on top of the rangefinder.
Does somebody have experience with similar setup?
Is it possible to compensate somehow high position of optical finder for precise framing?