Time to remember how to tune a 1920 1 bbl carburetor

I've got the /6 in my 1973 Duster running. I took my time with it. I got rid of the CDI ignition, and today I went over the vacuum hoses and found a few leaks or just plain unplugged hoses. I replaced the distributor vacuum advance hose, and the hose going to the fuel vapor canister purge port. The PCV hose and the carb vent to vapor canister hose looked okay. I also disconnected the vacuum hose going to the power brake booster and tried to suck through it, it seems to not be leaking.

I also bought a timing light for the first time in 20+ years and checked the timing. It's got about 4 degrees advance with the distributor vacuum advance hose unplugged, and around 16-20 with it plugged in. I was cheap and got the #3551 timing light at Autozone, they didn't have the #3555 with the dial back knob option.

So the engine runs, but once it warms up, getting it to idle right is a problem. It will only idle around 1500 rpms or so, no less. I tried the needle valve from 1-1/2 to 3 turns, didn't seem to matter. I've got the idle adjustment screw turned in about 5-1/2 turns or so, making sure it is off the fast idle cam. But once it is idling fast, if I turn the screw in only 1/4 of a turn, it stalls out.

And it is not fun to have to do the old move of pull the throttle open by hand to put fuel in the intake, reach inside the car to crank it, and as soon as it starts, get your hand back to the carburetor FAST, to pump the throttle more or it will die.

Any ideas where the problem may be, that it will not idle any slower once warmed up?

I was able to drive the car around the storage lot briefly, but it takes some fast moves to keep pumping the gas and put the shifter in D or R during the brief second where engine rpm slows down, then keep pumping the gas to keep it running.

This Holley 1920 is the #7031 version. I noticed during the carburetor rebuild I did that the main fuel tube leading into the main bore was shooting carb cleaner out as I sprayed through it, but from only 1 or 2 holes, I wonder if one or more is still clogged. And how to clean it?

I used 90 octane ethanol free gas from Sheetz, what we used to refer to as "GAS".

I paid attention to which way I put the carb to intake gasket on, as it is not the same both ways or flipped upside down. But the gasket was close to blocking the idle adjustment screw, I wonder if I might need to trim it a bit so the idle screw can function better. Should have done that the first time.