Intake leaking 440????!?!?!?!?

I know you can get a valley pan for these big blocks to eliminate using them as the intake gasket. I think I am going to try and get on and just use the intake gaskets that the factory style pan comes with.. I see that sealing a lot better than a metal tray... With that being said, If I were to decide to get my intake milled to fix any imperfections, how much should I have them take off?