Bobby, do you mean like a window net, or do you mean like a Safecraft left-side or center net?
For the former, my cage has tabs welded on top for the mounting bar, and the bottom of the net has straps that thread around the door-bars - allowing me to push the net as far out as I can.
For the latter, I had my cagebuilder weld the post that the net attaches to at the furthest forward part of the window. The net attaches behind my seat on my firewall.
I can send pictures if you want.
Side-Note, for safety related soft-things (harnesses/nets, etc), I'll never use something other than Safecraft ever again. It's expensive, but the highest quality belts/nets/hardware I've ever seen.