Finder question

I have an old dbl lens reflex camera "viewer" lens that's about 22mm diam. by 75mm FL. Just for kicks I taped it onto the end of an old 90* prism diagonal and slapped a (scrapped) Tasco bino WA EP (about 20 some mm FL at 65* AFOV) into the 1 1/4 barrel and tried it out as a "something between a 1X reflex and a real-finder" finder. In short it work really well! About 15* FOV at about 3.7X that still give an exit pupil of about 6.5mm. It also cuts through the light pollution MUCH better than a red-dot where I live and is still wide angle enough to get onto an object with ease (and is about 1/4 the weight of a "traditional" 7X50 finder to boot).

So - am I missing something here? Seems to me at 3 to 4 power anything larger than a 20-25mm objective is wasted exit pupil size anyway, and the resulting (smaller) finder is not a lot bigger than many 1X reflex sights that can't help cut through the light haze.

Any comments?

Sounds like a winner for l.p. conditions to me, Tom. Maybe there's a market for a 4x25mm finder of good optical quality with a 65 degree apparent and 16d true field! Heck, even with a conventional and likely to work better at that focal length eyepiece of, say, 40d apparent field, you'd still have a 10 degree true field, AND some extra light grasp and magnification over the unit types.