You need to make sure you only tap into the galley, you don't go all the way through into the inside of the casing. The bottom hole you use the small oil squirter hole as a pilot hole to center the main hole. You do not want to be drilling any holes through the inner wall of the casing.
I guess it takes a special type of person to build a warrior instead of just buying another quad. With warrior parts so cheap I'm nickel and diming my way to having very few stock parts.