Here is what MOB shared with me when I was working up a naked C10 project:
"for the gages I highly suggest a set of e-bay ZX1000r Ninja gages. circa 1986-1990, they are plug and play, and also give you an active voltmeter, you do have to snip the white wire on the Conni harness side though, as it will be useless, and you will have a kickstand switch error light on all the time(on the ninja cluster) as the clock wire is going to be connecting to that."
This is what he used on COGZILLA. Looks like you are on the right track.