i recently got a Watameter II rangefinder that I’m going to use with a scale focus Voigtlander Bessa. The Watameter is in excellent condition but the rangefinder patch is barely visible. I experimented with several filters I have, holding it over the main viewfinder to see if it improved visibility of the rangefinder patch, which it seemed to primarily by darkening the main view. I’m hesitant to put a filter over the rangefinder window because it’s already so dim, but what are the best options for the best contrast? I plan to buy a gel filter that I can cut down and install semi permanently.