I had not finished installing all the wing tip fairing anchor nuts the last time I worked on them. So I installed all the remaining anchor nuts along the edges. Then I cut the wing tip fairing nav light lens blank into two pieces, taped them to the fairing, marked them for trimming, then trimmed and fitted progressively until I had a nice fit. I drilled the holes for the nav light lens retaining screws, countersunk the holes and installed the anchor nuts inside the fairings. Finally I installed the fairings on the wings and insured a good fit there too. Some iterations were needed.
Wing tip fairing nav light lens fitted for trimming