Andy,
Sorry to hear of your clutch probs. You may have an easier fix by changing the slave or master diameter. Larger on the master and/or smaller on the slave so less pedal yields more throw.
The annular slave on the Tremec is from a late model Mustang with V6, as I said, but a search of the web yielded no info on a factory stock setup. I did find an outfit that specializes on annular slaves, Dorman Clutch. Summit sells some of their stuff. They list a slave for a 2006 V6 Mustang, which would have the T5 - a late model of it; can't guarantee the bolt pattern is the same, but I would be surprised if they changed it. Or perhaps match the slave to the vehicle type that the tranny came out of.
I don't know if the stock one is a push or pull - I would assume a push but I have seen advertisements of similar looking units as both push and pull. I can tell you it mounts directly to the front snout ot the T5, just like this Dorman, with the integral throwout pointing forward and the hydrolic input toward the tranny.
I may have the same issue when I hook this up to the TVR master.... You may as well - and have to change the master even with this annular slave.
Here's a pic of the Dorman unit.