The only thing I'd suggest Tom is you make sure that pillar mount is for your Mk4 golf. You dont wanna be messing around trying to get it to fit when you can purchase one thats identical fitment to your existing pillar trim.
I've been trying to figure out what to do with my 2 carbon fibre gauges for the Supertouring forever now. I really dont think a pillar mount would look right, I dont want to hack at the dash and I dont want them stood on top either as they look crap I think. I think I'm going to try a twin gauge pillar trim to mount them.