Personally, I'd pass on the kilt pin (why poke holes in your new kilt anyway?), and go with a cap badge for your bonnet, like the 3.5 cm enameled "collectors" crest from the RAF museum;


I wear an enameled Legion crest on my uniform glen, and quite like it.

I avoid military issue insignia myself, but if that's what you're after, you might try this one from Robin Finnegan,
.

I'd also contact Ms. Lare and see if she can send you a swatch of RAF tartan big enough for a badge backing for your tam or balmoral, especially if you go with the sta-brite type badge; much cooler than the standard, run-of-the-mill black grosgrain ribbon.