I'd never looked very close at the carbs because on colder days up to that point it seemed to run fine up to about 60 or 70 when it would sometimes start missing sometimes not so much. I was assuming it was something else altogether the whole time. I was double and triple checking the servos motor functions, cable play lengths, looking for pull throughs and dirty sticky power valves; all that sort of stuff. It was dumb luck seeing the over flow and changing the float levels was just a hunch. I was 7 hours from home (3 families rented a house in Iron River, Mi. over Spring break), I didn't have float valves which I assumed may be getting old and thus worn out, and we were all going for another ride the next afternoon. The ride we were on was so stinking bad, I had to try something! So,I set mine at the 11-1/2'ish mark and hoped for the best. It worked, the next ride was a blast and I've not been into the carbs since. If you can find brand new float valves, I'd suggest what you said, set them in the middle of the range. My sled only had just over 6000 miles when it began acting up, and while I don't know how long float valves should last, once I went to the minimum float level setting, mine are still closing gas off like they should.
so u can do the calculation