I have a variety of orbs but am looking for suggestions on how to store them - as compact as possible.
Not sure what you are referring to as orbs. Christmas ornaments? Can you use egg cartons?
Decorative orbs - Pier 1 has them to use in baskets, etc as fillers. They are shaped like a ball - about 4-5 inches around.
How large? You could get styrofoam and scrape out the shape of the bottom so they rest in a curve. Carve each resting spot so that they don't touch each other. If you have a lot, maybe stack them in a styrofoam cooler.
About 4-5 inches - shaped like a ball.