Idle Transfer Slot on secondaries?

The reason I am asking is that I am finding that the idle mixtures are having a negligible effect with vacuum/idle. I assumed the transition slots were opened too far. It’s not see pic.

Also Idle needs to be 1100RPM in Park and drops to 850RPM in gear. I don’t want to start drilling if this isn’t the issue but it still appears to want more air? I have no adjustable air bleeds.

Would my next step be drilling out the air bleeds and putting in metering screws? I don’t really know where to go from here….

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