Hi Brick.
My experience with just under 1/2” preload was that I had to push the pedal to the floor or sometimes it would nibble second on an up shift. After about 1,000 miles I could not speed shift into second and sometimes it would nibble second on a downshift. I thought it was a synchro problem and also there might be flex in the clutch pedal and bracket from the stiff pressure plate. What I found was nibbled gear and synchronizer teeth and burnt, transferred metal on the backside of second gear. Weird, the bearings looked perfect but that gear had gouged the shaft and that raised ring on the shaft is full of cracks. Nobody I have spoke with has seen this failure before so I don’t know what I did wrong.
I used Tremec’s brand lube. This time I’m using Mobile 1. I will use the 1/2” spacer behind the slave so I am sure to have all the travel I can get. If this doesn’t work I will try the GT500 master cylinder I have read about.