The fence on my miter gauge is 2.5" tall for reference.  Standard 3/4" x 3/8" bar.  I made it to mount to the side of my bandsaw so it's out of the way when not in use.  You WILL need access to the back of whatever you are mounting to to install nuts and washers unless you want to remix it and not have the bolt heads recessed.  Uses 2ea 1/4-20 x 4 hex bolts.  F3D and STP are included if you want to remix.

Suggestions only:
4 walls
20% infill
I added modifiers to increase walls around the holes just to be safe