I'm not sure if they'll have the same ones in stock or not, but you can try the dust plugs that High Point Scientific sells.
I bought some stuff from HPS a few months back and included some of their 1.25" & 2" plugs in with the order. The plugs are white in color but more of a translucent plastic than typical plugs I've gotten, and they also seem to be a little softer material. Although they're still tapered they fit just a little tighter than all my other plugs.
I typically tighten the plugs in slightly to help hold them in, which works fine with compression rings, but I'm not sure if it'll help any in a 1.25" ClickLock. One of my diagonals is a 2" twist lock (AT2D) and tightening a dust plug doesn't seem to help in keeping it from falling out.
EDIT: Here's a link to them ->
https://www.highpoin...h-barrels-epdp1
I not sure what I was smokin' at the time to have paid $2/plug. I must've been needing them bad or was fed up with losing them at the time, because I ordered a big ol' bag of 1.25" & 2" 
Edited by AstroApe, 08 June 2024 - 12:45 PM.