Thanks

Lt, The size if the letters are based on a formula from the equivalent of the FAA back in the 1930's. The size is based on a percentage of the cord of the wing. The spacing is based on the width of the letters; each major part being 4". On the top wing, the spacing was pretty easy but the bottom I had to contend with the inspection rings. I varied the spacing, giving more after the NC but kept everything else the same distance apart and avoided the inspection rings that way. It took a long time to figure it out. I ended up using CAD on my laptop to draw each letter to scale where I could move them around on a sale drawing of the wing to avoid the inspection rings and the high points of the rib. Next, I made paper cut outs of everything before I applied any tape. The layout took me about 15 hours. The owner had drawn out each letter on graph paper to match the style WACO had used so that put me way ahead. Every wing is going to be different; depending on the size of the letters, the quantity of letters and numbers, and what letters they are. The N is much harder to layout and takes more space than the number 1 but keep in mind they each have the same basic building block, 30" tall and 4" wide. Each letter, other than a 1, is 14-1/2" wide so I start with squares that size and go from there. All in all, it comes down to making it look balanced and with good spacing. Lots of different ways to do it.

@@martyfeehan2043 I will have a much easier time with 12” letters on my fuselage, however, it still looks time consuming. I haven’t searched yet, but I am hoping that someone makes paper or vinyl numbers that can be used to make things easier. That likely wasn’t an option for your wing work where it has to be customized by necessity.