So it probably comes down to non-CHDK related things - like price, image quality, ruggedness, battery life, size etc
Yes, on that basis I would go for the more robust 'A' series such as the A620 (which I have).
They are compatible with the plugs provided with the DC/DC converter.
You obviously do not want, and are not able, to make dummy fittings to adapt external power to some recent cameras.
Image resolution is not an issue because you presumably want no higher resolution than 1,920×1,080.
Your use of 'AV' is slightly puzzling, do you mean automatic exposure (AE) mode ?
On Canon cameras, Av refers to aperture value.
Note that many cameras do not have an aperture, they have a neutral-density filter that swings into position.
How many cameras do you need, where will they be located ?
