If you are ever looking for a "US" distributor, let me know. Not sure what the price difference winds up being, but Priority Mail, especially some of the smaller "envelope" or box items have been fast and efficient for me and offer that all important tracking and signature.
The mail and postal service in general has been getting very iffy. I deal more in the fashion world and have been turning over select designer clothing items for the last 15 years or so... I found a niche segment I know well and it also has dove-tailed nicely where now I want to do more of the shooting and less of the selling.
My point though, a fair amount of my traffic is international... both when I am sourcing as when I am selling, especially with the US dollar in the tank. It used to be regular air mail was o.k. expect around Christmas, now... Not so much... Some items I have got from the UK in the last month have arrived in two weeks... another I am waiting on and had to file, but to be honest, I think since I got it for about half to a 3rd what I expected it to go for, I don't think it was really ever sent. These days, out of the US, it has to be either Priority Mail or UPS in general, delivery confirmation and tracking is necessity, and what I hate, and is real scummy, PayPal and Ebay DO NOT FORCE the signature option once the item gets over two hundred... Especially when you do shipping through them, they know the rules... no signature, no protection.
Hope all of this gets smoother for you... from the small research I have done, your adapters appear to be a godsend, so I just want them around and available for when I finally have a lens to use them with