Pedro,
I used a small machinist metal measuring caliper and locked it down tight at a 1/4 inch wide setting. Then I laid the caliper over top a section of 1/4 inch wide tape and made a bunch of identical 1/48 inch squares.
In 1/48 scale, this worked out to be a perfect 12 inch scale square at 1 to 1 real life size. I was lucky here, because once I started laying it out on the model, it turns out the ground crews most likely used the same 12 inch square measurement on the real plane.
I used my good old eyeballs to match the little tape squares to an existing picture I had available of "Light House Louie". I started laying out the little squares of tape individually, and it looked like this:
Then I sprayed the area black and it looked like this.
Once I removed the tape, I realized that I had mixed my paint too thin. This allowed some of the black to seep under the tape, so I had to do a little bit of touch up work afterwards. It was not hard to touch up using a small paint brush.
Granted these are flat panels, but it was a little tricky where the rudder / fin fillet mated against the fuselage, since this is a compound curve area.
Hope this helps... 🙂
