To split one humbucker, you'ld put red/white on the center terminal, (as you said), but if it was me, I'd do the "top" terminal to ground. I prefer split mode when the knob is up. Although, there are exceptions. I have my Stag Mag split when the knob is down.
You don't need to connect the black hot wire to the switch at all. Look at this Duncan diagram:
http://www.seymourduncan.com/support...y-w-split.html
The "blue" terminals of the pot are the normal three terminals of the volume or tone pot. Connect them as normal. Again, study some of the Duncan schematics. (On the main page under "Support".)