To install Snow Leopard (or complete the installation to 10.6.8), follow the last link in my signature block.
To install Lion, see the UniBeast link in my signature block.
Note: NotShy's MultiBeast Configuration is old and several of those items he picked are now defaults in MultiBeast v3.10+ for Snow Leopard - see page 3 of the MultiBeast Features document that comes with the MultiBeast zip file. For instance, the default boot loader is Chimera, the 64bit Apple Screen Boot Option and the MacPro3,1 is the default System Definition. You'll want the defaults. Same thing for MultiBeast for Lion v4.2+.
For other appropriate MultiBeast configurations, see the MultiBeast Configurations screen snapshots in my signature block. Also look for similar build descriptions in the User Builds forum section to see how others were successful.