Stringing a race car chassis is an effective way to align all four corners. With a kart there is no camber or toe adjustment at the rear so stringing would only be useful for the front end and there are simpler ways to set toe on a kart. To be honest all you really need is tape measure to set total toe and an angle finder to check the camber.
When I string my Formula Ford or Atlantic car I use a set of stringing bars that are built specifically for each chassis. The bars are configured to set the strings on each side parallel to and equal distant from the CL of the chassis just wide enough to clear the outside of the tires at the wider end of the car. The track widths on the race cars are much closer to equal than your typical kart so the measurements from the strings to the wheels are similar at both ends of the cars. On a kart the rear is usually much wider than the front so the string setup leaves more room for measuring error on the front end. Yes, it is a method that can be used but for general upkeep and tuning it is not practical.