Right.Limited to 4S then.
8 X 1600 = 12.8 Kg of thrust maximum on those props but reduce that total due to power losses in the X8 configuration.Think along the lines of 10Kg thrust lifting 6.3Kg at maximum throttle.and you'd get your video.
13 inch would give a theoretical boost too 14.4Kg but again X8 losses reduce that.But it would lift a bit more.
I see wheels.So it's a self propelled octocopter ? And,most importsntly to save new hardware costs,can it lose a fair bit of weight ?