After tightening, be sure that you haven't over tightened. The eternal search for minimum drips is important, but let's remember what you are really doing here. The packing gland / stuffing box, etc... needs to be lubricated to minimize overheating. With a standard flax stuffed gland, there needs to be enough access to cooling water to keep the unit no more than warm to the touch when running in gear. A VERY careful touch of the nut will indicate whether you are too tight. Warm to the touch maybe, but never hot to the touch. A little water in the bilge is a small price to pay to keep the shaft true.