It's easy to experiment with the idle feed restriction on the Holley style carburetor. What I recommend doing is getting a piece of stranded copper wire, stripping the end, cutting it off and using one of the strands to hook through the existing idle feed restrictor. Most of the time they will be about .013 diameter, just use about a 1/2 inch long piece that you can place in there and bend over so it can't come out unless you remove the metering block.
Try it, start at 1 1/2 turns on the screw and see how it responds, you can do it in the back and in the front. If it's better then you know that you need to go to a smaller idle feed and by about how much less area. A couple of thousanths can be a big change and make a real difference in the part throttle driveability.
Any sufficiently advanced technology is indistinguishable from magic --Arthur C. Clarke