I suspect the dog has hit upon the crux of it. I believe he is correct in the 3 foot seperation, and even if he is not, that amount of seperation is really needed for the lights to be distinguished from one another. That basically relegates them to a hoist on a spreader halyard on everything but the largest of sailboats. I like the idea of them, in that they make the boat visible, uniquely, at sea, and keep the running lights below where they are easily distinguished inshore. Most offshore traffic is not really concerned with which sidelight they may, or may not, be seeing on a sailboat, due to the slowness of sailboats. The tricolor's advantage is in it's visibility versus specific information conveyed.
Are your sidelights obscured ahead by your bow pulpit? Do you get backscatter at night off the pulpit? On the ships we'd paint anything forward of them, that reflected aft, flat black. Or are you scared of the dark and don't need them? (G)
“Scientists are people who build the Brooklyn Bridge and then buy it.”
Wm. F. Buckley, Jr.