Jess, for a quick test of your hypothesis, pop the column shroud off and disconnect the two-wire connector (grey and brown, IIRC) for the horn and CC. This will rule out the new wheel as a source of draw.
Did you do anything for the CC? The Grant slipring I have is all one piece (as opposed to the 3 channel piece that is OEM). I was real hinky about this since there is power and ground feeding to this location, and having both shorted together in a one piece slipring didn't seem copacetic.
Good luck bud.