So you're getting clutch movement via the master and slave. But I agree that it could be air in the system. The hydraulic system moves very little fluid and the placement of the master cylinder relative to the slave cylinder does not lend itself to air bubbles always working their way out. The master is lower than the slave since the master is on the floor in the pedals and the slave is higher up up on top of the trans. So air bubbles tend to not work their way out if you're not forcefully bleeding the system.
You could try removing the slave from the top of the trans and hanging it down below the floor of the car. Then bleed it the same way with your vacuum bleeder. This will help the air bubbles find their way down the line via the fluid pushing them along and not getting hung up in a high spot along the way? Worth a try......
Did you mess with the linkage in the pedals at all? I found that adjusting the positioning of the pedal linkage (the linkage that deals with the assist/return spring) did not produce the desired result I was looking for, which was a lower clutch engagement point. The G50 pedal typically has an engagement point near the very end of the clutch pedal travel. So I fiddled with the linkage and it made matters worse in that I couldn't get the clutch to disengage and thus I couldn't select gears. I was using the Bentley manual at the time and it actually has some good information in it about the G50 pedal linkage. It provides a better diagram of the linkage where there's an eccentric bolt and has an explanation that's clearer than the factory Porsche manual.
Speaking of the factory manual, the directive in the Porsche manual that forbids the flywheel resurfacing is based upon the tall rubber damper of the original clutch disc. The reason being is that they foresee the top of the rubber damper brought closer to the "roof" of the clutch housing where the release bearing is hanging low, potentially causing interference.
However, when you do away with the tall rubber damper by installing a spring-centered disc, which is typically at least a couple inches shorter in height than the rubber unit, the issue of clutch housing interference is eliminated.
So you can indeed resurface the '87-'89 flywheel. Like John said you need to do a double cut to maintain the same placement of the clutch housing relative to the flywheel friction surface and use a spring center disc.
First picture below is the page from the '84-'87 Tech Spec book about the '87 flywheel. Second picture is a page from the factory 84'-'89 Carrera addendum to the '72-'83 911 factory manual (see yellow highlighted box)
I've personally seen resurfaced G50 flywheels work in a couple of cars I had my hands on (mine and a couple of local friends) and we had no issues. It's also something that's been mentioned here on the forum for a long time and others have had success with it as well. Edit..... porschyard beat me to it.
I'll send you a PM and I can get you the portion of the factory manual that covers the G50 clutch control- pedals, master cylinder, bleeding hydraulic system, etc.
