I am going to award you a West KY redneck star for that idea on the using the clear rubber hose to determine the true fuel level in the carb.
I have rebuilt my old carb a number of times over the years and set the float per the directions, but i really never knew how to determine the true fuel level in the carb.
your method would work.
my carb will leak sometimes, i have tried brass needle, rubber tip needle and new seats, but never really solved the problem completely.
the electric fuel cutoff might be the right way to go, but my way works as long as i remember to cut the fuel off.