I had the same question here. I called Progressive, they said they're out of stock and won't have any for a few weeks. Anyone have a good (non-Progressive) source for some? I'm down to the point of calling up a manufacturer and asking about a custom job, but that sounds expensive.
Subtopic: What material is being used these days? I've heard "poly", but does that mean polyurethane?
"I've heard "poly", but does that mean polyurethane?"
yes
check out some VTX forums. some are using nylon bushings for OEM shocks which will work, very low cost, but don't last as long as poly. some are using porous bronze bushings.
if u like what they are doing u could size a set for the progressives or maybe on the VTX sites somebody has already done it.
https://www.vtxcafe.com/threads/rear-shock-bushings.47393/nylon works better for rotational applications which shock bushings are not doing.
however many VTX riders love them
https://grassrootsmotorsports.com/forum/grm/nylon-bushings/50124/page1/