wing tip light mounting

[prkaye]

For mounting the Whelen combo nav/strobe lights, no template was given for the cutouts in the tip. It looks to me like a 1 3/8" hole towards the front for the nav bulb extrusion, and a smaller rectangular hole for the DSUB connector from back of the the strobe portion.
As for positioning on the tip, I'm guessnig that since no specs were given exact placement is not critical?
The Whelen instructinos say to use 3 countersunk #6 screws to mount hte baseplate, but looking at the baseplate itself, only 2 of the holes in the baseplate are countersunk.
Also, should I mount the platenuts directly to teh fiberglass, or epoxy in some sort of aluminum backplate first?