Another update for my forum amigos.
Finally figured out how I'm going to correct the kink in the front wall (see photos) and mount an upper track for the hanger doors. More on that at another time, this update is mostly about working towards finishing the base. Along those lines I found the following article from the web, that when modified to my specific conditions, very helpful.
Antrvm Ratvs - KISS display bases
Unlike on the authors bases where the tarmac is plastic sheet, mine are heavy paper stock, so a bit of prep needed to be done before I could scribe in the concrete joints and cracks. I sprayed the entire base with several light coats of white sandable automotive primer (see photo for exact brand) in two separate spraying sessions, 24 hours apart, sanding it after each session with 320 grade sandpaper. When that was done I had a nice firm surface to work with. I ignored the article authors admonishment to scribe the concrete panel joints very irregularly, insisting as I would that any contractor that works for me pour concrete not only neatly, but in 12.5' x 25' sections as my research indicated was the best size for longterm durability. (Seriously, I actually researched this. Is it any wonder why I never actually complete anything?) After all the scribing was done to my satisfaction, it was time to lay down some paint.
Again ignoring the paint shade order suggested by author for no good reason, I laid down 3 different acrylic concrete paints with my Badger single action airbrush. First the entire base was covered with Polly Scale Concrete, then the centers of each panel where lightened with Polly Scale Aged Concrete and finally the edges where defined with the darkest shade of all, Vallejo Model Air 71.131 Concrete. This, as I said, is kind of a reverse of what the author of the article suggested and in fact all I have ever read on the subject...and yet I still can't tell you what my motivation for doing it this was. Anyway, against all odds, it looks the part! I'm not finished with it yet, but at this point what do you guys think? Be honest.