Theoretically, the clear film should be the blackest black of which your paper/paper developer combination is capable---and at an exposure which is the minimum exposure time needed to render that clear film area your negative basic black on the paper.

When you really get going, use plenty of paper developer. I don't measure exactly: I just always use the next larger up tray size--which is usually an 11x14 tray of developer for an 8x print.