IIRC Trilogy Autocockers have the same valve practically as the SS25, and Palmers makes a Trilogy Cocker valve.
Yep, went to their site. Low Turbulence Valve Assembly - Trilogy [PPSP029] - $37.00 : Palmers Pursuit Shop!, Where Custom Still Means Something
I remember a long time ago when I bought the SS25 when it first came out I put one of these in there. I think I had to only modify the bottom of the valve because it was solid with an indent for the valve retaining nut. The SS25 retaining nut didn't quite fit into the one on the Trilogy valve, slight dremel work and it fit fine.
The reason I did this was because the SS25 valve was produced with a delrin valve stem assembly. It did not seal with the back of the valve, it allowed blowback gas to push the hammer back partially and create hammer bounce (aka "farting"). I did this modification because the Palmer's cup valve stem was metal and machined perfectly for the valve, allowed absolutely no blowback gas and completely fixed the hammer bounce issue.
Okay, just ordered one. I'll let you know my results when I get it in.