I think he’s more asking about 15” hoop & head on a 14” shell with spacers under the lugs than drums where the bearing edges contact point is 13 3/4” on a 14” snare.LA Camcos, Sonor 3ply teardrops . Two examples of legendary sustain , both undersized shells .
Poor reading comprehension.... They only made the Extenders for a short time. They were in MD for a little while and then disappeared. Tama made timp toms for a short time too. They used the swivel lugs that are used on the gong bass drums and took a head an inch larger than the shell. They didn't last long either.I can't tell if some people still aren't picking it up, or just want to talk about undersized shells.
I've never heard of Pearl extenders. A quick and cheap way to produce that design, rather than commit to a newly cast lug. They should of carried it through the resonant side.