First
Check for vac leaks again. If it's still got leaks, you will be chasing your tail!

Second
Mark try this. Get it started and twist the intial up more. Whatever you observe now, turn it up another 4 degrees and see if you can get it to idle down. See if the timing setting you observed at high idls has changed to a lower number with the new lower idle speed. As long as it starts without kicking back, bump it 2* at a time until it becomes hard to start, then back it off 2*. The numbers that were suggested are just that, suggestions, let the engine tell you what it wants.

third...
Do you have any control of the primary side of the carb. Do the idle mix screws do anything right now. Can you see any fuel dripping in from the boosters?

Here's some stuff that should be present on that engine.

Vacuum at idle of about 850-900 should be in the 13-15 area minimum.
It should idle cleanly at 850-900 rpm
In gear it should drop maybe 100 rpm.