Building a drone that isn't for racing - more utilitarian. The drone without battery and motors is 225g and can support up to a 7" prop. Ideally it uses a 3s battery but this can be changed to 4s if need be (main concern is size + weight). The ultimate goal is longest flight time (ideally 20mins+) without having a heavy drone (ideally no heavier than 600-700g). I feel like this type of drone is in a odd spot as most motor manufacturers cater to super heavy (9/10" +) with 2216+ or FPV/racing with high KV and torque with short flight time. 

I've been considering 1806 with 5/6" props with 3s or 4s battery. Looking into having an 1808 made to give greater stator surface area.

Appreciate any thoughts.

Check Chris Lemire youtube channel. His 7" does 60min+ using low KV 2204 with CF props.