I wouldn't bother with an oiler. You can just add a few drops to each tool's inlet before you use it. A good water/oil separator and filter is a great thing to have. You do not want more than one or two quick disconnects in the air line. They are fairly restrictive and will severely limit air flow, especially to air hungry tools like impact wrenches. Also, add a pressure regulator before the water separator if you don't already have one. The pressure drop helps the water to fall out of the air by cooling it.

Drain your tank regularly and enjoy.

Paint & Body Shop moderator
A lone amateur built the Ark. A large group of professionals built the Titanic.