Jill,
I use the B1 box and I can get 10 Colossal bulbs in one of those boxes. I have to place them strategically(for lack of a better word) to make them fit too!!
Besides the Colossal bulbs I have a BUNCH of Super Colossal bulbs too!! Some are absolutely incredible!! Almost like freaks of nature.
They are some of the BIGGEST caladium bulbs I've even seen and I've seen a few caladium bulbs in my days!!
biLL