This is all good advice. UPS will pack your tins for you, but they will charge you for it. The up side to this is the painter can re-use all of the packing material for the ride home. Insurance is also a good idea, again they WILL charge you for it. But if you get enough, it would pay for any damages.
I like to wrap parts in a bath towel, and then tape it secure. Then completely mummify it in bubble wrap. Then fill the box with wadded-up paper and peanuts.
I usually won't ship for at least a week after I finish a job, so the clear has time to cure out a little. Nothing like packing materials leaving imprints on your fresh parts!
BTW, when will you be ready???