You are correct, it's a combination of two adjustments. Here is a repost of how I adjust the ball stud and cable. I have been speaking with Dave English about using the GM tool to adjust the ball stud but after thinking and looking at the adjustment with this tool I believe this approach will accomplish the same result.
Ok, here goes. What many people do on these cars is mistakenly adjust the nut on the end of the cable to get there pedal freeplay. This happens because some people don't even know about the clutch ball pivot on the top right side of the bellhousing.
What you want to do is make sure that the clutch fork is pulled all the way to the rear of the car. The return spring should accomplish this, but just make sure it is all the way back. Now you want to adjust the cable by turning the nut at the clutch fork to remove all the slack. You must also make sure that the pedal is all the way up, it helps to have someone pull the pedal up against the rubber bump stop while you adjust the nut to remove any slack in the cable. What you are trying to accomplish is, clutch fork all the way back, pedal all the way up, no slack in the cable. Once this is done now you can adjust the pivot ball on top of the bellhousing. The best way to do it is to actually measure the gap between the clutch disc and the flywheel when the pedal is depressed to the floor. For a diaphram clutch you should have about .030. The only problem is there is no easy way to measure this without an inspection hole in the bottom of the bellhousing. I drilled a small hole in mine, big enough to insert my feeler gauge. It has to be drilled at the point where the disc mates with the flywheel. At this point you loosen the large locknut on the adjusting screw and turn the pivot ball to get the proper gap with the pedal depressed, then lock down the locknut. Since most folks don't have any way of measuring this gap, the more common method of adjusting the pivot ball to result in 1" of pedal freelplay will also work fine. The important thing to remember is that you want the freeplay to be the result of a gap between the throwout bearing and the pressure plate fingers. Having freeplay as a result of a loose cable is not what you want. That's why you want to make sure that there is no slack in the cable to throw off your freeplay measurement. With no slack in the cable, the clutch fork will begin moving immediately when you start to depress the pedal. The clutch fork and throwout bearing will also begin to move immediately, taking up the small gap between the throwout bearing and pressure plate fingers (which gives you your pedal freeplay) and all will work fine. With the cable and pivot ball properly adjusted the throwout bearing will not be in contact with the pressure plate once the pedal is up and there will be no chance of clutch slippage since the pressure plate will be allowed to fully engage. You can fine tune the stud to suit your preference but this puts you very close to where it should be. The important thing is to not have any slack in the cable when you are done, that is just wasted motion and it does not accomplish freeplay where you need it. Different brands of pressure plates and throwout bearings will effect where the stud needs to be. Some clutch assemblies are a little thicker and not all "short" throwout bearings are the same length. Hope this makes sense, if not ask me again!
*** I am adding this simple step by step process which summarizes the above.
1) Have someone pull the clutch pedal against the rubber bump stop.
2) pull clutch fork all the way toward the rear of the bellhousing
3) adjust cable nut to remove any slack
4) Loosen nut on pivot ball stud
5) adjust pivot stud to obtain 3/4" - 1" freeplay at clutch pedal.
6) recheck cable to make sure there is no slack