I wouldn't modify (enlarge) the small holes in the head gaskets we're talking about there. Larger holes could alter coolant flow patterns through the heads in unexpected ways.

Incidentally, any air pockets that remain in an engine will slowly be absorbed by the water/coolant mixture. Over a few days or a couple weeks, the air will disappear. This assumes the air pocket is below the uppermost coolant level in the cooling system.

Jim