Thanks for the good ideas CapriR 
Yes, prior to mounting I’ve lubed both the bead area and the tire with soapy water and/or a thin layer of silicone rubber. The bead on the tire isn’t sticking against the rim edge at all. Like you suggest, a second person on hand would indeed solve the puzzle, but few of my friends and neighbors find my fascination with diy’er tire mounting very interesting … lol … in fact none of them do … so either I need more friends, or I need a single person solution.
I did another experiment today along these lines, used the ideas proffered above, and decided the key to the final task of diy’er tire mounting solution is a gadget that will hold one side of the upper bead from unraveling; as the work from the other side is completed. Toward this end today I clamped a piece of wood to the rim at that point with an 8 inch c-clamp. It actually worked pretty well, for a first try. It totally prevented the bead on that side from unravelling. And I was able to complete the top-side mounting straight away. The only problem was that the clamp came loose just as I completed the other side, and the wood flew off who knows where … lol … but I think I’m onto a workable solution finally; some kind of wood & clamp technique should do the trick. There’s probably a gadget that does this trick already for sale somewhere, but I’ve never run across it. I did see one u-tube video where locking pliers were used right on the bead area of the rim, but I don’t think it’s a very good idea b/c the pliers might mar the rim’s bead area and create a leak.