I just got out my CV 35mm finder... it's the newer round metal style. In regard to glasses, I think there will be individual differences in the finder use depending on the glasses, and how far the lens is from your eye. I think mine are relatively close... With the finder contacting the glasses lens, I note some slight darkening/vignetting around the edges, but the bright-line frame is easily visible in its entirety, and a tiny (darkened) area outside of that as well. Without glasses the CV finder is very bright at the edges and a useful amount is visible around the framelines.
This is better than the 35mm framelines in my M2. Brighter, and the framelines are more easily visible. Without glasses the M2's frames are visible all at once only in peripheral vision at the extremes. With glasses, I can just see the top and bottom lines but I need to move my eye back and forth to see the left and right frame edges.
