>Question about Timing<

[Mobilehomie]

I recently had the heads rebuild on my son's '81 Sierra 1500. After much tweaking and tuning, I have replaced the carb with a re-manufactured unit, and have been messing with the timing. I don't think the mechanical advance is working. When I set the timing with truck in park, vacuum disconnected and port plugged I do not get any advance when I throttle it. When I hook up the vacuum it is only getting about a 10* curve. I realize the spec says to set initial at 6 degrees, I have always added ~ 2 degrees per 1,000 ft elevation (we live at 4,200 ft) so I have it at 12* initial and total is only 22*~ 23*....
Is that enough total advance? Should I just lock?