It's no different in practical terms than ordering from SP EU. All you have to do is plug the tracking number into one of the sites that will show the progress then use the number with USPS when it lands here, usually just clicking on their tracking shows everything unless it hasn't been picked up yet. I've never had an experience where the tracking details couldn't be found, but someone has to input.
My order would have arrived today, which would be 10 days from shipping notice, but I had it shipped to my business address so I'll get my pipes on Monday! 10 days is pretty typical for my orders from them, but sometimes when they arrive here they can get stuck for a bit (just hope yours didn't go to Chicago, lol, mine was in and out of New York in a day and I assume that's where they send them these days and it's not November/December, so that's a plus).