I've got the same Avroto 2814 770kv motors on my quad and I fly it with 12x3.8 APC props. They seem to perform best with this size. Although I've only tried smaller sizes, nothing larger.
With a 4500mah 4s pack, AUW is 2857g or 6.3lbs. I usually only fly for 6 minutes but on manual mode 50% is...