Modroc / Plaster of Paris

Hi there,
I've recently made a pregnancy cast of my bump using modroc (plaster of paris bandage) but I'm not convinced that it's strong enough to decorate yet. I've run out of modroc but I do have lots of regular plaster of paris (not on bandage). Do you think this would be suitable to just layer over the top of the cast or paint on top? I'm not sure if I should just buy more of the bandages, paper mache the inside or give the plaster a go.

Any tips or advice for strengthening the cast?

Many thanks!