Mikhail; I think you are overthinking this, a number of people have indicated you can lower the float a very small amount and accomplish what you are asking. If you want the be very precise on this, set it at 8mm or whatever - run it for a time and see if that is what works. Myself and many others in this forum and on TT have had good results from the non-precise method to get proven results. As an aside; set the float at a pre-determined level, move the carb back to vertical, then re-check it. Did it come back to precisely what you had set it at, nine times out of ten it will be different. JMO