Delete that outside line.
If you are tearing in completely down, you may want to consider modifying it to full flow, like in the article in the "tech tips" section on the left sidebar of this website.
Leave the hole sizes in the internal line fittings alone. They are they to help regulate the amount of oil to the top of the head.
Taking the "trap" out of the line shouldn't hurt anything, but as you say, it will be taken proper care of from now on, so....
You didn't say what year the engine is, but if it's a 53-57...
Use the Felpro of Victor gasket sets. The last Victor I got from Patrick's and it included the rubber rear main seal and the head gasket had the front water passages restricted to push more water to the back of the block, the Felpro I had before that didn't. The copper gaskets are just stock replacements that are thicker and require re-torqing. It's also the only head gasket I've ever blown. Of course, if the engine is earlier than '53, it may be your only choice.
