Well, Pidge and Hunk have been doing that mostly... along with Coran. Coran has the most experience with them, but the whole creation process was apparently some weird mysterious thing. So, we're all learning what they can do as we go along. They have an endless supply of energy with quintessence and are nearly indestructible because of the comet ore.

Honestly, though... you'd be better asking Pidge or Hunk than me. They can probably tell you more.