So I'm having a little difficulty figuring something out here.

I have a novation remote sl (mk1) I have it all set up nice and neat. All the mapping is working swimmingly.

I'm using sonar platinum.

I also have a Korg nanokontrol2.

Here is what I'm trying to accomplish here:

I want to use the remote sl the same way it is now. I have it set up as a generic surface. And I manually mapped everything with the template editor and the generic surface assignment window.

I want the Korg to control the busses and the master volume and maybe the metronome and preview.

How do I set this up? If I set up another generic surface, the options I want to control aren't listed.

This may be more advanced than my feeble mind can handle.

I'm tempted to let it be the same setup as the novation. Just in case I want to mix some stuff without being married to the big keyboard if I don't need it.

Would that be more practical?

I would look at using ACT. I haven't tried two Generic surfaces together but I do run several ACT surfaces in tandem with a Generic Surface.
 
I actually use ACT and the generic surface at the same time on the same unit. I use ACT for knob, button and fader control with my ZED-R16 and the generic surface for transport control.
 
I have a video on my youtube page that shows how to setup ACT devices.