I wonder if your clutch master cylinder is the same size as the US cars. My clutch disengages just a bit before the pedal hits the floor and that's with the rod adjusted all the way out. It's enough for full disengagement but I'd like it to be more in the middle of the pedal's travel. I bought a 7/8 master cylinder from Wilwood that should help out by moving more fluid. If your pivot ball is OK and you have no leaks in the hydraulic system, I would look into getting a larger clutch master cylinder. I believe the one I got was around 90usd.
BTW, I wouldn't go shimming up the pivot ball, it could cause the throw out bearing to ride on the pressure plate constantly and wear it out prematurely.
Brandon