Yup, you definitely have to spell out your customs declaration requirements for any out of country seller. I always do every single time, even if I buy from the same seller!

UPS is a fu(king nightmare. I would rather have the seller take my watch tie it to the foot of a crow and shoot at it to scare it into flight in my general direction than to ship with UPS. I really can't understand how they remain in business...

Canada post has been good lately for what it's worth... Got a beautiful Patek from EU with no customs delay, and a multiple watch package from Puretime with only 1 day delay. Great!