I'm building a 4 port brake for the 300 WSM I have in the works. I have the ports angled back @ 20°. My question is, which of these ways would be best? Should the entry into the first port be drilled through the same size for the 5/8 threads (9/16") or necked down like in the picture of the four port (.328)? Right now I have it built like the drawing. The other picture is one that I made for my Creedmoor with the muzzle even with the back wall.