Brilliant minds think alike...and fast: thanks to Vulpes and Stokessd for getting me exactly what I need: simple, no extra unnecessary metal (you would'nt believe some of the insanity-bought from a bike store no doubt-that I've seen for this purpose).
These clamps should do the trick.
To answer Vulpes: yes, both my Motobecane Mirage (~ 1978), and Raleigh Supercourse (1981) have no braze-ons to anchor a rack. I'm assuming if I purchased (then or now) a frame specifically built for touring, that I'd see this feature?
Can't really recall the last time I saw any 'vintage lightweight' with such anchors, then again, the above frames have no braze-ons for water bottle cages either. The Supercourse (which I bought new then), was marketed as an 'entry-level' racing bike, believe it or not.
Thanks for the quick solution, BJK