Hope you have your problem solved by now. But if not, I owned a few pre 70 beetles and it took quite a bit of force to disingage the clutch......If the original pedal you have is very short from the pivot point to the cable hook up......then it is using a lot of leverage to decrease amount of force needed to operate.......while giving it a short throw.
Have you thought of using an after market hyd. kit, like they sell for dune buggies etc.?