Normally an oil finish requires many coats. I use 000 steel wool between coats. Eventhalpy you get a nice gloss finish or you use the steel woil for a satin/matte finish. More to it though than wipe on, wipe off.
The problem is the 10-22 wood is not walnut generally and it's sort of like staining and finishing a 2x4. Hard to make it look "good".
A cool custom paint job wood look better to me.
Yes both of those mag wells will require fitting. I have found the Brown to require a little less fitting than the S and A but that could have just been the gun. The last S&A I did seemed to take forever to get it just right
I've just about worn my first one out, wouldn't be without one. I pre-clean all my brass before tumbling and that's just one of the uses for a sonic cleaner.
A little off the subject but speaking of casting, I ain't real impressed the marks in the middle area either. That area should be relatively smooth as it rides on the disconnector.....just sayin'
One thing I always do and actually check pretty often is dropping the slide with the release and make sure it doesn't drop to half cock or follows especially since we deactivate the grip safety on our comp guns.
Single sided safety? I don't know what the "Pro" finish is but you can certainlly get a blue one for it. Fitting is not that hard (depending on brand), although it's easy to ruin a new one. It's one of those a little at a time deals til she fits.