Boogle
I know what to do and how to do it thanks. It doesn't help that the numbers published for CBP don't work and the handler (Signature) are like the mandatory chocolate fire guard that comes with lots of US handlers.
Your comment "Exhaustive and annoying " sums it up though. Getting info from most US handling agents is near on impossible as they either can't be bothered to reply or are clueless when they do.
I managed to find a number for CBP at KMSP and spoke with an officer there. He gave me the low down on requirements and an email address. He also added "we don't normally use email". Useful when the fax number doesn't work.