From the luck-out department, I discovered this thread the day AFTER sending a large box to Sweden. Said box had the following characteristics: USPS, 63 pounds, yeast samples (b/c it was sloshing a little so didn't want to go with glassware), $30 declared value. Basically, I sent it off based on some very loose research I had done, then read this thread and sweated bullets for 2 weeks. The luck part...cleared both sides no problem, even arrived 4 days early.
Going forward, though, I think I'll go with the conventional wisdom...now that I know what it is!