I received the two Omni-Stands I ordered from CorSec Engineering. I got the 5" bases. They are clear acrylic but come with paper backing on both sides -- which I suppose makes one of them "fronting" -- and a metal threaded receptor in the center. The paper is still on in the photos below. The two telescoping rods have spherical magnets on the top, one 1/4" and the other 3/8".
I had a chance to spend a couple hours at my stoodio between running errands today, and couldn't wait to test them out. They are exactly what I'm looking for.
I've used small nuts glued on the underside of the planes, as close to the center of gravity as I could get. I don't remember what size (saved the label in the container in which I'm storing them.) The smaller, 1/4" magnet is just strong enough to hold the planes in position. The larger magnet is almost a bit too strong, but I think I may keep a couple of those around in case I end up with some larger/heavier planes.
One mistake I made on the Fokker DR.1 was that I glued the nut appropriate for balance, but not far enough back from the plane that spans the landing struts. So it fits a little awkwardly. I'm not certain I can fix that at this point.
Almost done with the first DR.1. Not sure I got the colors & effect exactly right. Should look better with the markings on it.
So I'll definitely be picking up some more of the Omni-Stands.
I'm also looking into the hex map issue. The two current options under consideration are 72" x 48" felt European Field map from Hotz Mats, or having my own design printed locally on 72" x 48" outdoor banner vinyl. The former is about $60, the latter is $140.
EDIT: It looks like CorSec makes some potentially nice looking mats as well. I'll take that into consideration too.