Thank you for the responses - I checked & yeah I'm getting +12V between fuse #13 & the ground (and the lightbulb works fine coming off the gray wire). I recall the red/white was on the lower-left of the cluster, relative to the front - but i could be wrong, reaching behind the instrumental panel was a true ****. Anyway, over the weekend I'll have time to look behind there again.
Umm, kind of a dumb questions: this coil, what & where is it? I'm speculating it's gonna come down to running a wire directly from it per your suggestions.