Hard starting when cold

This may be grasping at straws, but worth consideration...

Remove the accelerator pump from the carb. How much fuel is in the column? Sometimes the leather on the pump dries up and doesn't make a good seal. This can lead to fuel evaporation, which in turn can make it harder to start the car. I had the same issue with mine, replaced the pump, and the problem was solved.

Forgot to mention, if you're going to test the fuel level under the pump, let the car sit over night first (and make sure the car was running before you park it for the night). Then check the level the next morning. Of course, don't pump the throttle or try and start the car before checking.