You may want to check out Pirate Ship as another option, they discount UPS and USPS prices significantly.
I was also able to buy thick wall box and packing materials from UHaul that worked out great to ship a ST.
This is the Pirate Ship quote. Been using them for a while now. Dimensions I had to work with, but weight was a guess on my part, assuming 10 total pounds of packing materials added to the weight of the BB2.