I just dug through my acrylic paint drawer and found the bottle..it's indeed Tamiya X-6 Gloss Orange (dullcoated, obviously.) As I recall, j-aircraft had a formula for IJAAF Trainer Orange, but it was X-6 with a tiny bit of other colors added. I didn't think the difference would be that noticable, and I was feeling lazy, so I just went "out of the bottle." I did lighten it a bit for the control surfaces, since the fabric tended to fade more quickly.
Thanks for the compliments, BTW. I used a vac canopy from a Falcon set, and good old IPMS Hinomarus. The Kanji character came from the kit d