dumb question about dual display set up with sli config

So I've never run dual monitors with my 680 sli rig before. I currently run DVI to my 1080p Asus lcd.

I want to get an Asus VG248QE so I can use that screen for gaming and have the other screen for other tasks. Apparently the VG248QE is display port only. Would I just plug that into the same 680 that the other is using DVI on? Or should I plug it into the other 680?

Or--If I use DP on one, do I have to use it for both?

thanks for any help/suggestions

I used HDMI, both DVI, and DP on my only 670.
My DP didn't use as much bandwidth as you will be, but I doubt it's going to be an issue. I only mention it because, using dual link DVI disables my second DVI.

I can't comment on SLi.