To separate the idle cam from the choke

Timing.
Plum your vacuum advance to one of those thermo-vacuum switches that switch between ported and manifold vacuums, based off the water temperature. You can get them in a variety of different switch points. In this way the idle speed remains relatively stable as the thermo is reducing signal to the can as the coolant warms up, which reduces the timing assist. It took me a couple of tries to get the right device, but I thought it was pretty slick. And it was automatic
IIRC your Vcan is over 20* which might be a lil much, depending on your initial, but maybe your cold engine will not suck it all in. Besides, both of those are adjustable.

What I eventually did was install a dash-mounted, dial-back, timing control with a range of 15 degrees. Different plan of attack, but same results. The dial is usually set to option; 5* retard and 10* advance. So on a cold engine I can dial in 10 over the 14 in the Initial. That's lots enough for my combo.