What are the NEC rules for holes in a wooden wall top plate? Specifically, how far apart do the holes need to be and what is the max diameter of a hole? In NEC 300-4 I found "...holes shall be bored so that the edge of the hole is not less than 1 1/4 in. (31.8 mm) from the nearest edge of the wood member." Is this all there is regarding this topic? Thanks.
Don't make it larger than half the top plate's width
Since the size of holes in a top plate is a structural concern, not an electrical concern, you need to be looking in the IRC (or other building code) for these details, not the NEC. In particular, IRC R602.6.1 states that a metal top plate tie strap is needed for a notch or hole in a load-bearing top plate that extends through over half of the top plate's width; unless you're running fat conduit or SE cable, you won't come close to this, though.