lead tetraoxide or bismuth oxide for Dragon Eggs

I am going to be making some 2mm microstars and I was wondering what
would be better? lead tetraoxide(lead va****, not good) or bismuth
oxide. here are the formula's that i am looking at using depending on
which one i choose.

also, does anybody know of anywhere i can get either of the chemicals.
I have checked most of the normal pyro chemical suppliers and can't
seem to find it.

any help is greatly appreciated,

Deren