If the dough is tearing when you are transferring to the peel, then it is probably over proofed. Pizza dough needs to have the right amount of strength, extensibility and elasticity. You need to be able to stretch it out easily, but not too easily.
I tried the Pilsbury dough once and found it to be total garbage. It's much easier and better to make your own. As an alternative, your local market or Trader Joes might carry some in bags.
You should be able to stretch it out over the counter, and then transfer to the prepared peel without it losing it's shape. Here's a good video that shows you how to open a dough:
https://www.youtube.com/watch?v=GtAeKM_f2WUJust made one last night. My son's favorite - clam and bacon! This was 16" but I usually make 18-19 inch.