I had this dillema as well when I was putting a UHF in (not gauges, but same principle).
I didn't want to cut or drill anything as I always wanted to be able to take the thing out and not have the car look like it's full of holes. The simple solution was to figure out where I wanted to mount each part, and then get replacement trim panels from a wrecker.
That way you can cut/drill to your heart's content, and if you get sick of it later on and/or just want to return it to the stocker look, it's dead simple to remove and replace with the original trims..