Cj95, I usually mask / paint my hinomarus. I wish I had 1/72 scale to send you, but I usually do 1/48. I have tons of those. If you want, if you can give me diameters, I could try to cut them down and send them your way, but if you're up to it, I would encourage you to try the masking.
I've used two methods: 1) take a compass (like you use in a math class) and instead of a pencil attach an x-acto. They even make these new x-actos which are made for cutting curves that would work excellently. or 2) buy at a arts and craft store a circle cutter. I think they are made for scrapbooking, so they tend to cut bigger circles, but you can get ones that go down pretty small.
Other people might have other / better methods, but both have worked for me.
Chris in Japan, I can't speak with an official voice, but I think it would be great to have you along.
Leon