I think you can use the Kreg jig on your 2X2 if you so desire. It's just that, with it's 15 degree preset, you will probably not get a heavy enough screw, or long enough in there.
I don't know off the top of my head, but what is the recommended screw length for the Kreg jig going from a 2X into a 2X?
-- Blue skies. Dan Rossi Carnegie Mellon University. E-Mail: dr25@xxxxxxxxxxxxxx Tel: (412) 268-9081