dp, your setup looks very similar to the one I made for my twin-cam Moggy, after I discovered I couldn't get the previous owner's hydraulic setup to work:
Marina clutch pedal with a pivot fork welded on:
The Marina pedal box with Fiat 131 clutch cable fitted:
This setup worked pretty well, though I always had a rather high clutch pedal, and one that rubbed up slightly against the steering column (hence why I bevelled arcs half way along the pedal in the first pic, to provide some clearance) - ideally of course, the pedal should be heated up and bent to clear the column, and IIRC, ohc_turbo's pedals are already modded in such a way...
ohc_turbo, clutch slip and low biting point could be caused by incorrect adjustment of the operating mechanism, and possibly a worn clutch release bearing - though I guess you would have checked/changed that when you fitted a new clutch plate?