Great decision by changing your props. DJI props are less forgiving and I've read numerous posts about them self destructing in flight. I used APC 10x4.7 props on my F450 with a 3s 6000 mah lipo battery, 30 amp esc, AVROTO motors and a GoPro hard mounted to my craft. My flight times we're 8 minutes with the heavy setup.
The APC props are cheap enough that it will allow you to experiment with different sizes and won't self destruct in flaight. Ive seen post of people using Graupner 8 inch props on their F450. If you search the posts on the forum you'll be able to see the flight times that people are getting with their setups. You'll have to consider the weight that you want to lift when choosing props.
A good reference is Multirotor ecalc:
http://www.ecalc.ch/xcoptercalc_e.htm
I used a heavy battery, motors and larger props because those were the salvageable parts from my Hexacopter after its crash. It flew fine with the 10 inch props.
Good props are APC, Graupner, and Xoar. APC are extremely forgiving especially if you are just learning to fly. They may be the cheapest thing you put on your craft, but can cost you a lot of money if they break in flight. Don't buy into the full carbon fiber props. I had a Gemfan 10x4.7 carbon fiber break with less than five minutes of flight.
Securing your props are equally important. The washer goes on top of the prop. Do not over tighten the nut because on some props it'll cause hairline fractures which will cause your blades to seperate from the hub.
There are lock nuts available at hardware stores that will prevent the vibration from shaking the nut loose. There are many YouTube videos of unsecured props flying off as well as prop breaks.
