Holley 1945 /6 choke opening too fast?

as to the accelerator pump;
not only must it squirt as opposed to dribble, it must begin to do so immediately when it is tickled. If it hesitates, so will the engine.
A cold engine will not burn dribbling fuel. The droplets are too big and will not vaporize on the way down the cold intake runners. Rather, that fuel will stick to the runners and never get there in time, just as the raindrops stick to your side-windows at 60 mph, and slowly slide down and rearwards. AS the runners warm up, that river of gas will tear off the manifold and enter the chamber, some of it adding to what came in in the usual way, and now she's horrible rich. And some of it will pass straight out the tailpipes unburned.
Stale gas will only exacerbate this. The fuel of today, in a vented container,like your fueltank, will begin to lose it's potency in just a week. The lightest components evaporate at temps below 95*F. These light components are what lights the heavier ones. Without them, you get driveability issues like....hesitations, stumbles, bogs, and stalling. Low compression just makes it worse. The heaviest components might take over 400*F to flame up.

Fuel color is a key to telling how old the gas is and it's associated potency. Fresh is clear. slightly yellow is still ok, but full yellow is making trouble. Red is garbage, it won't hardly light laying on your concrete garage floor. Orange is between garbage and trouble. It will light with an open flame but will smoke and stutter on the floor.

The heat passage under your carb is there to evaporate the puddling fuel and to warm up your intake runners. Evaporation takes heat. So the gas while evaporating, is sucking the heat up like a sponge.
If the heat-riser is frozen open, this defeats the whole system, but now the problem is compounded by the evaporating fuel.
Not sure about a 70Duster, but the later ones had their
intake air temp regulated to be at about 85*F, by the little sampling device mounted on the floor of the air cleaner housing. The carb is calibrated for that temp.
At WOT, the snorkle-mounted Thermac valve opens to allow fresh cold air in. The Thermac valve mixes cold air with the heated air available thru the heat-stove. This is to prevent cold-running problems; once the intake air is over 85*F, the system returns to normal.

So to recap; most of your cold-start systems are not working, hence the problems you are experiencing.

Another thing worth mentioning is your ignition advance mechanisms. Cold-starts need them to be working. Frozen flyweights, broken springs and a ruptured diaphragm will all cause troubles for you. And so will too-wide plug gaps with a weak coil. And a too-low fuel level makes pull-over difficult, also causing a hesitation.