I used the same elements but instead of a balloon I used one of the bowls. I spread the baseline on the inside and place the soaked butterflies on top. Once dried, they came off very easily and kept the shape of the bowl pretty well. Finally, I spray painted them.
This is what it looks like. Bellow, beside the larger butterfly bowl (tutorial here).
And here with a large tea light.
It fits beautifully, by pure chance, I did not plan it!
Anyway, i hope you will give this technique a try. It is fun, pretty cheap and effective results. What more can you ask for?