OK, that explains that. But you a situation where such fine work on the springs should not be necessary. If the blades are so close as to touch or almost touch the bores to get down to proper idle speed, then something is not right. Sorry, but the throttle plates should be slightly open like .015", not right up against the bores.
I still suspect that there is some air getting in that you need to shut off, so that the primary blades will be open more at the right idle speed. Look down in the secondary bores and see how closed off those are; if they are propped open some, then the secondary stop screw should be turned down on a Holley. I never had a 1406 so don't know how the secondary stop is managed (besides the lockout linkage from the primary).
I have also had a loose primary to secondary lockout linkage (the one that keeps the secondary closed 'til the primaries are open to X degrees; it this what you are calling the actuator lever?). If that is loose, then the secondaries will pop open a bit regardless of any secondary stop setting and let more air in and raise the idle speed; you won't see this unless you look when the car is idling. I think you said this linkage was a bit loose? If you tighten it up to about a .001" or .002" tolerance, the secondaries will be sure to be closed. Again, I am talking Holley talk but the 1406 has to have similar link that has to keep the secondaries closed down properly at idle.
And pinch that PCV hose or cover the PCV's inlet at idle and see how much that effects the idle.