I need to check these forums more often, I may have almost been helpful for someone around here.
So far I've found that for the disappearing helmsmen, a minimum/maximum of 10.455/10.456 is a good trade-off. This way in stormy weather, it will be somewhat rare for the helmsmen to appear and disappear instantaneously, and the boat will be submerged for only 1-3 seconds before the helmsmen appear as they should in real life.