[pneumo]

I just had another thought, since you're going to build a custom master cylinder mount anyway, why not move the point where the master rod attaches to the clutch pedal? Just drill another hole in the clutch pedal arm and move it up closer to the pedal arms pivot. Then just move the master up a little so the rod coming out of the master isn't at an angle. That should change the leverage so you have less pedal pressure. Theoretically that should do the trick, but I haven't looked under the dash yet to see if the pedal arm has room for another hole.