If you want the ultimate cleaning method for carburettors it is ultrasonic cleaning with a mild degreasing agent diluted with water.
Ebay these days list a variety of stainless ultrasonic baths in various litre capacities up to about 6 litres.
To go beyond this is commercial equipment costing thousands of dollars.
I have succesfully cleaned plenty of bike carbs this way and it is brilliant bringing them up like new and most importantly it will clean inside all the small passages in the carb,the only other way to do this is to drill out the passages and replug them after with lead shot from a gun supply shop.
This will duplicate the OE manufacturing method and give the results you need.
A series carbs have always been an issue with their small passages in the idle circuits,no doubt the emmission spec Dellorto's are the same in this regard,unless the passages in the carb body are clean no ammount of jetting changes will make it work well.
Remember unless all the inside parts are clean then the outside of the carbs is irrelevant.