George --
I feed pellets -- a 42% protein pellet from Zeigler Mills up in PA -- but I've never seen a garss carp come into feed. It's usually trout first in the chow line, followed by the dozen or so channel cats left in my pond, and then a few hybrid sunfish. But never a grass carp, that I have witnessed.
And, Dave, that deer stand idea is neat. I've been thinking about putting one in just for the purpose of fish watching and photography (and if it scares away the neighborhood great blue heron, well, that's okay too!). -- Mike