So I'm looking for the "right" place (or maybe the "wrong" places) to put a through-hole for an NMO antenna mount on my Extended cab 2014 STX. I havent taken the headliner down yet and was hoping to avoid doing that for this job. I was planning on installing deadcenter in the roof (i dont have a sunroof) but i'm worried about hitting a cross member in the roof when i drill.

The roof has 7 "ribs" that stick up, and the are two places where the ribs end and there's a "flat" zone that goes all the way from side to side on the roof. The flat area would be my preferred drill site, in the center. (i checked at least on of these will miss the dome light underneath, which i also dont want to be right on top of.

Has anyone done this in their truck and have a good spot that works?
Thanks
-jcp-