Hey Big Poppa came out nice I was going to do exactly what you did. Just by chance on YouTube I spotted this other mount. I do prefer the look of your solution all being in the one piece pillar rather then the over pillar the one I ordered is See how it goes!
Hey
Hey I am sure your all done by now with your mounting. But Ive been searching for a solution for my nGauge as well. I ordered this from BlowbyBlow Racing
2015-17 Mustang BBR Pillar Pod