@solderpunk well, the ultimate rangefinder is leica with retractable lens 🙂 but older FED and Zorki can do a good job as well. My Kiev 4 is not that smaller compared to SLR, but it is fun to shoot with. Your Yashica will be great, enjoy it. Also, check Petri cameras if you find them somewhere - https://en.wikipedia.org/wiki/Petri_Camera