I'm going to pull the trigger on another unit that will be dedicated to a 360 I'm having installed. I currently have a 10" Onix at the console and 10" Helix Mega G2N at the bow, with an Ultrex, everything is linked.

I'd prefer to get a used unit to save $$$, minimum screen size of 9". I'm not sure what unit will work best and don't know if I need to network the units?