Bill,
I'll be happy to answer your question regarding Flynn's bunker styles. Over the 70 or 80 years since Flynn was building his golf courses, maintenance pracitices have changed on some of his courses resulting in a different look to his bunkering. If you recently played the US Naval Academy course, where all the bunkers have been remodeled, you'd think he sometimes designed bathtub like bunkers with grass faces all around yet these are not the original style.
Flynn had a variety of styles depending upon the kind of site he was working on. The locale (seaside, parkland, mountain, etc) influenced the types of grasses he used (he was an early experty on turf for golf courses) and thus the finished look. Flynn's bunkering at Indian Creek, Shinnecock Hills, Boca Raton, Atlantic City CC, etc had a certain style. Flynn's bunkering at Merion, TCC in Brookline, Rolling Green, Philadelphia CC, etc all had sand flashed high on the faces. He clearly liked visibility and the psychological effect it had on the golfer. But not all of Flynn's bunkering on individual courses or in general were flashed all the way up with sand. It was a general principal of his though. I'll try and put together a photo montage of various Flynn bunkers so you can get a feel for them. Its something I need to do for the layout of our book and I think it will demonstrate the variety of styles best.