Well, as uncomfortable as I was with the direction I was headed in fabricating the position light bases, I felt iw as time to go another route. I need to fabricate new mounting bases and use the top blocks I had cut for the positipon lights.
I will recess the area where the lights will fit and insert the base plate inside of it. I can then rivet the base and foam core directly to the wing tip frame. It looks good in my mind. I just need to see how it actually looks in practice.