Thanks Ron. I just tested mine and it won't hold on a slope. I know the pedal module is good, the intermediate cable is new from 2 years ago so it is highly unlikely to be stretched. The equalizer is tightened up properly now. I doubt the issue would be cable stretch anyway as I've never had an issue with cable stretch on any of my vehicles, and I've kept one of them until it was 27 years old. That pretty much leaves parking brake shoes, adjustments, and discs.
1) I do suspect I have an issue with one shoe which could be causing this problem.
2) I may not have removed enough of the rust ridge on the parking brake drum. This may have prevented me from getting the shoes adjusted out enough to seat within specification. I'll take my dremel to that ridge as well.
3) One thing to note is the parking brake actuator at the wheel. When servicing this, make sure it remains engaged with the adjuster. I will have to check for this, but I know the first time I installed it, the actuator slipped out and I had to back everything off again and reinstall.