I have the Unity Tool, had some friends that were hardcore that used these. Someone was selling on ebay didn't know what it was beyond some type of RC tool. Best enay deal ever $10. It is great for tweak but for toe there is know way to make sure the chassis is straight. I run zero toe so I have been using 1mm graph paper. I line it up the grid through the two holes on the front and back of my 12l4 and on my crc I use the front hole and make the rear parallel to lines.
I Just use this software and set the grid for 1mm and thicker lines at 1cm.
http://pharm.kuleuven.be/pharbio/gpaper.htm