Although it is hard to tell from the pic, I doubt that that amount of wear is causing the problem.
I have always found 4 bbl Holleys to have a lot of shaft clearance, even when new, compared to other brands, so 2 bbls probably the same.
Worn shafts [ if they are worn ] do not cause fuel to drip. I suspect that you have a high fuel level issue which is causing the idle problem; flooding could be the cause because of leaking n/seat, leaking/binding float etc. You are probably only seeing the external leakage, engine off, because the engine is drawing the fuel IN when it is running.
