As one who occasionally scratch-builds 'weird' stuff like made-up spaceships and submarines, any and every 'pod' shape gets saved as potential future cargo/fuel/sensor candidates. As for paint...I've got a lifetime supply of clear blow-molded plastic bubbles of the sort Chick-fil-A sauces come in, purchased in bulk for pennies back in the '90s, that are my go-to for doing a quick mix-and-throw away job.
Whatever works! 
