I did this for the first time recently, and a lot of it depends on how the musicians will be setup, and what you'll have access to. In my case the band was set up in a half circle, with (in clockwise order): acoustic guitar, drums, vocals, bass, keyboard, and lead guitar. I set up dead center in the middle of everyone running at about 3' high and Healy Method omni. I was running an R4 at the time and was able to take a line out of a speaker that was setup only for vocals (no one else was miked, just used their amps direct). Mixing the 2 tracks of just vocals with the 2 mic tracks turned out amazing.
I see you're running a 660, do you have access to any other deck? If so, I'd run pretty much exactly what I did if you can, that's also assuming you have the omni caps for the C4s.