Carb heat shield . . . anyone try this?

Just use the Edelbrock 2732 part. It won't raise the carb as much, and that makes the choke / linkage easier.

Part of your problem maybe the fuel pump / plumbing. Just a tiny air leak (crack) on the suction side rubber hoses can let the line from the tank to the pump leak back in to the tank - losing prime.

A tired fuel pump can leak back through the check valves too.

If either of those things happen, it will be hard to start after sitting. It will take a lot of cranking to suck the fuel to the pump.

Add the insulator. Check all of the lines, from the tank to the pump.

B.