Carter 4 Barrel Top Cover Leaking

[1] Fuel slosh is going to 'wet' the gasket, even with the correct float level.
[2] The airhorn could be warped.
[3] Do NOT use an extra AH gasket as it changes the position of the met rods in the jets. If the shop suggested this, find another shop...
[4] In the pic, there is a small hole below the centre screw. Could that be the leakage point? I think it is just a vent, do not know why it is needed, maybe anti percolation vent. You could try blocking it off.