Howard,, I got what you were saying,, I thought it was pretty clear,, anyway,
I am curious,, where are the checks,, blocks, and other square shapes,, How on earth will we ever recognize your airplane if its not orange with square shaped trim elements,,
is this some devious plot to align yourself with the infamous JCT stunt orginization, oh, wait,, yeah never mind
as to files and working with.
what I do here, I draw my mask files in CAD,, then I draw a bounding box around them of a known size,, say 24 x 12,, I select all the elements in the box,, and "control C" ( keyboard copy command), then I open my cutting software and use "control V" (Keyboard paste command)into the blank "page" in my cutting software.
I can then select the bounding box, and in my tools on the cutting software I can tell it to make that box, ( and all elements contained) scaled to the exact size, in this case 24x12. This has worked really well for me.
However, I will tell you that frisket will stretch slightly as you place it if you are not dead carefull,, In fact I try to design around that fact when I lay out a scheme to avoid that sort of thing. I do not like two trim colors butting together as a rule. However, you can use the mask you have, then with 1/4" tape, clean up the butted edge to avoid the small variences that are basically inevitable when working on a 3D surface..
Hopefully I have communicated what I am trying to,, short version,, use the mask to get as close,, and establish the NEW edge for color,, use the tape to clean up the existing edge,, yes it is laborious,, but it works well with a bit of patience