Why in the wide world of sports would you want to run a modern plasma cutter with an electric eye? I spent a month retrofitting one of the old eye controllers on an oxy/acel table and converting it so they could control it with MACH3. They wanted me to leave the design it so they could plug the eye back in and do back to that method. IT cost them an extra 1000.00 to make it dual purpose. To my knowledge after the first cut from the computer they have never used the eye again.
It was a pretty neat design since it's basically a servo system (even has a +-10V servo amp inside. Only problem is that it was designed to move (and trace a line) at 10 to 20 IPM for cuttin 3" > steel! I doubt it would accurately follow a line at 300 IPM for thin plasma cutting.
The "eye" needs a high contrast drawing (heavy black lines on white papaer). It also needs a line (not just an edge) since it senses it's way by measuring the error from both sides of a line. It won't "scan" a part and give you a drawing either. I doubt it could be used for that.
Your 100 times better off (unless you have lots of existing drawings of parts too big to scan that you need to continue to make) to use the CAD->CAM->Controller approach to generating parts.
There is no way that MACH is going to work with the old Burny.
The cheapest THC option is called a drag tip. Put on a drag tip and build a spring loaded floating head. Slam it down, pierce and drag it around. Works okay in simple parts where no cut is within about 3/4" of another. Good news is that when you get ready to do a real THC you can use the floating head for material sensing.