I find this a good subject for all to consider. I don't have any better answers, but my experience has been that FEDEX is usually the best way to ship heavy boxes. Also, I've read of people driving great distances to pick up their speakers from the speaker maker. A little time off, tour their facility, learn some stuff, get to hear some other speakers while you're there, good experience... and no speaker damage!
There are lots of speaker companies that ship heavy speakers every day. I wonder what their experience has been? I also wonder if there's a better way. I may contact a few and ask. Others could do the same and report back to this thread. Thanks.
-- Roy