For carb balancing, simplest method is to listen for the click as the throttles drop down closed,
Wind the tickover stops out. open the throttles a bit and let them shut, both should close together with no great difference. If you have removable air filters then it is a good idea to drop them off to hear what is going on.
Beyond that, any pair of vacuum gauges will get things even more accurate or have a read on how to make a water manometer in the tech tips on the main club website.