That last bit there is super important- I’ve only found success with hollys on the street after reducing the idle feed restrictions until the idle mixture screws gave a good idle at 1.5 turns out. I’ve found that at least in my congested neck of the woods most situations in traffic end up mostly cruising with such small throttle opening that you mostly feed the carb with the transfer slot and idle discharge port. The idle discharge ports are restricted by the corner idle screws but the slots use the IFRs as jets.

When you get best idle vacuum with the idle screws 1/2 or 3/4 turns out you’ll know what you have to do. I’m a fan of sticking guitar strings in the ifr but you can make jets out of brass set screws or buy fancy metering blocks. A wideband and a vacuum gauge makes it much easier to tune especially when you get around to using the power valve for wot- which can get tricky too if you race and the vacuum increases on the big end...