Welcome to the club
As an experienced RC-Pilot of all kind of remote controlled aircraft, You will find out, that '... Flying Vector Kites is a remote-control experience like no other .... ' (as Mike Gantt discribed in the Modelairplanenews Vector-Kite test, issued April/2010):
It is a bit of 'thrust pitch' heli flying, as well as 'electro soaring', and, a bit 'ultra slow flying' in combination with some 'easy stunts at low speed'.
And, may be, the main fact: You can fly as close to You as You want with that 320cm Eagle (and with other vector kites, too). At least, You can fly it like a sail plane, but not in the same way:
As all the Vector Kites are flying objects without any possibility of control without motor action, You at first allways should keep an eye on the voltage status of Your onboard LiPo. Some new RC radios deliver telemetric data about that, and give a warning signal, if the voltage comes closely to 3V of the LiPo-cells(or another value You programmed). Heli pilots meanwhile oftenly use telemetry.
On the other hand, although the wingload of vector kites is one of the lowest of all winged model aircraft, You cannot expect the same glide ratio, like a top soarer has:
Without motor thrust, the light EAGLE (and the other vector kites, too) reduces it's speed to a minimum, so the 'glide' is more a kind of 'sinking'.
This helps, if once You forgot about the capacity-status of Your LiPo battery, the motor stops, and the kite will not fly away from You for a longer distance.
If a short running LiPo occurs, just at that moment, when You have found upwinds like a termal bubble, it could be a bit problematic, to get the vector kite down, where You want.
Kite Aerial Photography: Vector Kites are ideal slow flying platforms for onboard cams. On my bigger deltas (350cm +), I take my 'normal' camera (Canon Powershot) onboard, and it makes good videos.
A 3grs. Minicam, like You have choosen, should be no problem.
LiPo size: I flew my Eagle with LiPos between 1050mA and 2200 mA.
With the larger LiPo, it lies a bit 'heavier' in the air, but You will get double the flight time.
Anyway: I wish You as lot of fun as I have with my Eagle(s)