depends on where you are and the support you get. Can I get Sonor in S. Africa? No, use a Pearl kit. Same with cymbals...if your endorsement deal cannot support you with equipment as you tour, feel free to use whats available.
yup - one is good, two is better
One to setup and play on for practice - one in cases for the road.
I have 3 duplicate kits. 1 in my home studio, 1 in our bands rehearsal space, and 1 in cases for gigs.