Another poor-hot-idle countermeasure: install a hot-idle compensator. About a decade before these started being built into (some) carburetors, Rochester Carburetor offered one configured as a universal aftermarket accessory. They called it the CarbAIRator and it worked just like the inbuilt kind, except it's adjustable. They show up on Feebay from time to time, such as
this one. Thread on a female pipe thread to hose barb adapter and tee it into your carburetor's choke pull-off hose.
