Gas monster

Ok now that yur getting on track, you gotta know that setting the timing at idle is not the best way to do it.
Your engine has four major timing requirements;
one for power, and
one at convertor stall,
and one for cruise-timing, and
one for idle.
after that it has another requirement that constantly varies with load and rpm, that is normally referred to as PT(PartThrottle Timing).
As for PT timing, this comes mostly from the vacuum can, but it is added to the mechanical timing. If the mechanical Timing is wrong, then so will be the PT timing. If you change the Mechanical timing, this will also change the PT timing.
So then, the PT timing is always worked out last.