Do you have at least the 3/8 inch or so spacer that used to come in the rebuild kits?

That made a huge difference in the starting of the last car I chased this problem down on. With just a thin paper gasket I’d get some longer cranking even on a hit start. That spacer got me quick light off and I could go about one week without much issue cold starting a car with no choke. Any longer and it was gas down the carb time. Electric pump would help the situation if you are up for that.