The smallest triangles I've ever seen are 1/4 inch.

SIG sells leading edge stock but it was not the right size or shape for my Uproar 60.
www.sigmfg.com > Building Equipment > Wood > Balsa Wood > Leading Edge
part munbers SIGB085 SIGB086 SIGB087

I used a Master Airscrew razor plane and a flexible foam sanding pad to shape the rectangle they sent in the kit. It took me 2 or 3 hours to do both but I'm pretty happy with the way it turned out. I had a gigantic pile of balsa shavings and sanding dust when I finished.