Hi Snapper,
You have a good eye. I have to admit that I struggle with finish build up in the corners of carving on every gun I build. I have never found a really good way to deal with it except to apply finish very thinly and slowly. Even then dust, particles, and finish still thicken in the corners and I rub them vigorously with a stiff natural bristle brush. That helps a lot but I can never remove all of the buildup everywhere. Certainly, this is almost no issue if I produce a low sheen "in-the-wood" oil finish, but on most guns I build, I am using or trying to emulate an oil-varnish finish, which can lead to build up. Another factor that plagues me, Snapper, is lighting. I have good lighting but you really have to work that lighting to see imperfections in the wood surface from carving and shaping, especially on light colored woods like maple . It always happens, that I think I have the background perfectly smooth and then later I examine the spot under low angle light and I find rough spots. I take care of all the spots I find, then after staining the wood and working the lighting, I find some more. I am not referring to gentle ripples caused by scraping, which I like and retain, but tool marks or shaping flaws. Then the real kicker is, after I think everything is good, I put finish on the stock. As the finish becomes a little shiny, inevitably I notice a few more spots that I missed. At that point, I live with them. My guns are a very human product, warts and all.
dave