Tips for tuning dual Carbs?

You can MAKE a manomemeter. The reason you need something like the old uni-syn device is for carbs that don't have individual vacuum ports which isolate vacuum from one to the other

Here.......

Down at the bottom, 'uni-syn instructions'

http://www.aircoolednut.com/erkson/ttt/engine/carbs/

Here

http://www.aircoolednut.com/erkson/ttt/engine/carbs/uni-syn-1.jpg

and

http://www.aircoolednut.com/erkson/ttt/engine/carbs/uni-syn-2.jpg

You can get pretty close by carefully LISTENING to each carb, if necessary use a length of scrap hose as a stethoscope