..."Curiousity question: the uni-knot slips under tension (aka hookup) and comes tight to the hookeye. Is that important if you keep tension on the line to insure that the hookset remains in place? ...."
I don't think the hookset is as much of a concern as abrasion iwould be on a single stranded loop, especially when there is always the possibility of abrasive rust in the hook eye. I can imagine that when you have a hook eye sliding back and forth on a short single strand of line in a loop while you're fighting a fish sooner or later it's going to break.
Thus the search for a knot which utilizes doubled-over line in the tying of a loop knot and tightens up to the hook eye under tension into a tidy tight knot. I'm sure the salt-water guys are probably familiar with a knot that would have these characteristics?