Gee I wonder if I should thread a nut on before making the cut, so I can.....
KIDDING -- can't believe how many times that admonition was repeated on this thread, mostly _after_ I had mentioned it. Whaddevz. Anyway, it's done. The local co-op had new "loaded" axles, with cones/spacers/washers/locknuts/balls, for $10. Cut was a breeze. I evened up the end and beveled the outside with the side of a cutoff wheel. Had to find the right mish-mash of spacers, locknuts, etc. to get the right spacing. When I spaced it with the freewheel spaced similar to my other 126 bikes, it would have required a LOT more dish. So I tweaked it some more (took advantage of different-thickness locknuts), which was much more favorable wrt dish, and of course, moved the freewheel to the right. Freewheel-to-dropout clearance is... er... close, but it works, and the chainline looks good just eyeballing it.
Still gotta pack the bearings and put the finishing touches on the truing. Thanks, all, for the insights/ideas, I'll def keep that DA axle in mind for future reference.