Hi Gang. I'm continuing to study. I found some information on the BING altitude compensating carburetors. I prefer to have a manual mixture adjustment. None the less, this article talks about the shape of the needle valve and the rationale for it. I'm certain that this information is going to be applicable and interesting to all who run the lake-derived carbs.
http://www.jabirupacific.com/pdf/CarbTune.pdf -- Glenn Martin, KR2 N1333A, Biloxi, MS