Timing help needed

One more snip from Shrinker.
Some of these things are context dependent, not absolute rules...

" If the vac is less at say 9" to 11" then the t-slot needs to be more exposed so the idle mixture screw will probably be best idle at around 0.5 to 0.75 turn off the seat. The Idle mixture screw is really a trim control for the slots contribution."