I am glad you posted the early ad for the TRIANGLE RADIUS ROD SUPPORT. They are much more common that the round ones around here. I drag home 3 triangle supports to every round support. I had always thought that the triangle support were something some local blacksmith had mad up in his shop. I always thought that the round supports would be stronger and look better
so I always use them.
I've posted this 1923 ad before:
My Coupelet had a support similar to the one shown in the add. It has has issues so I'm using a different style.
Notice the spelling error in the ad, BRABE instead of BRACE
Guess the spell check(er) didn't work. ;^)