What I have done for years is use two 8 foot florescent light tubes. Lash them to the bottom of the rear wheel (bungees before and after the wheel so they are snug against it) with the bike vertical using bungee cords, and prop the front of the tubes up with a 2x4 just forward of the front wheel. Have lots of burnt out tubes in the shop I save just for this. Becomes apparent very quickly if the bike is not tracking correctly. BTW, in reviewing the Kawasaki shop manual I do have to take some exception to their guidance on chain tension. I think it calls for between .5 and 1.5 inches; I would aim for the 1.5 inches minimum (I'm recalling this from memory as I don't have my manual in front of me at the moment. Point being, aim for the higher end of the spec.). The bottom end of the spec seems (to me, anyway) uncomfortably tight. Planning on doing a vid just on this topic soon, and am hitting up some local shops to donate some really badly worn sprockets and chains so that can be shown visually so people know what to look for. Anyway, personally, I advocate for running the chain on the looser side of the spec FWIW. Oh, and the calibration lines on the swing-arm are never, ever, equal or correct on anything I have ever worked on and trying to eyeball tracking is futile.