If at all possible I would try the air-bleed adjustment / test first.

I spent a significant amount of time getting my Carter TQ 9800 to idle nicely. Initially I went down the path of drilling the plates but that was a stop-gap measure. It only gave a very "static" setup, meaning as soon as something else changed the previous combination wasn't spot-on anymore.

Eventually I went studying the TQ circuits enough to understand how to re-work the TQ passages (by installing brass plugs that are drilled to a particular size) that actually gave me a poor-man's adjustable air-bleed configuration. This now means that as my jetting changes I simply go up or down the air-bleed size to make sure the idle ports still have enough fuel flowing to feed the motor. Co-incidentally (as expected) this approach also cleared up the part-throttle situation. The idle-to-primary transfer is much nicer now.

Now that I'm changing my motor I should be able to simply adjust the air-bleed sizes to get the TQ to flow the right amount of idle fuel.

BTW: Small block 360 motor, HE3844 hydrualic flat tappet cam (238/244, 108LSA), 21 initial advance, 35 total, 800 RPM idle speed, drops to 700-750 when in gear.