Did a little used LP shopping yesterday (thanks for the lead, Scott F!) and found a trashed Reprise
mono copy of Duane Eddy "The Biggest Twang of Them All" for $2, and a mint Santana "Marathon" for the same.
On my 1.6s the Duane Eddy was quiet, played great, but the stunning part is that this mono disc sounded 95% like stereo!
The music was a little (?) hokey, but I kept 'looking' at the instrument spread and thought "this CAN'T be mono!" Depth, width, soundstage, you name it, in spades.
Santana was better, but not by a huge amount. Go figure!