I just bought a P2, gimbal, 2 batteries, Gopro 3+ Black. Is it wise to charge the batteries to full after flying, or wait a few hours before flying again. How many hours does the charging process take. I'm obviously new and I have a lot of practice to do, think I should hold off on the extender. Finally I want FPV but have to wait. What is the biggest screen I can get? Thanks all.