Hi Suttlaw, I have a regular HRX and, after a few year, couldn't stand the JMW 12.6 tonearm any longer, so I found a way to put another one, and then two, and then three. If you take a look at my system, you will see that the slight mods required are completely reversible and self explanatory, and any local machine shop can do them. Be aware though, you have limited options for the tonearm that will take the place of the 12.5, you can only choose one whose cables don't exit from the bottom. As far as I know, the only arms with this provision are the Reed, that I have, and the Triplanar. I hope that helps, and sorry for my english.
Marco
Marco