Well, no luck finding the SAE connectors/plugs at Harbor Freight, and, shockingly, none at Advance Auto or AutoZone either, anthough it was strictly "no hable ingles" at the latter, so who knows?

Luckily I remembered that the Battery Tender also came with a 2nd set of cables with alligator clips on one end, so I jet on home and, sure enough, they have an inline fuse & SAE on the other end. In business.
But, now do I want the standard "cigar lighter" attachment, or the BMW-type Powerlet socket, which look smaller in diameter and is more expensive: both are "Great for cell phones, GPS units and heated vests!" The cell charger works "great!" now in my car's standard 12V hole, as does my little compressor. Go cheap with the Universal Cigar Lighter socket? :-/