Retune my entire carb after installing new heads?

With your four holes in the sec blades, plus the high idle speed, I wonder if you are getting nozzle drip in the secondaries. Less common in H carbs & clones, but it does happen given the right conditions.

Not sure if this could be done but maybe worth investigating: Four 0.100" holes is equivalent to 2 holes of 0.141" diam. Drill 2 holes through the body & the base near the air cleaner stud. Engine will get filtered air & holes in sec blades can be plugged.