Hitachi's are a direct copy of the SU, to the point where the floats and needles are interchangeable, and probably other bits, but that's all I've used in mine.

the tool you need to measure the vacuum and balance the carbs is a carb balancer or synchroniser. There's a few different types. Its going to be much quicker and better to see a visual gauge of the vacuum than trying to judge it by ear. You used to see them in any auto parts shop over here years ago, but carbs are a bit old fashioned these days. No idea about where to get them where you live, but would be very surprised if you can't find them on ebay.