I have typically held back 25% of the charges until the trophies arrive in the US and are inspected. I learned that you never pay for anything up front the hard way. (this is not just in dealing woith Outfitters)

By putting all of dipping and packing on the same bill with the Outfitter. And by putting all of the charges on a credit card you would have the right to contest the bill even if the Outfitter had been paid. Sort of a back door insurance policy.

The Outfitter would be paid sooner and the customer would still have some control over a fast arrival and the condition of the trophies.