At great risk of having blindness pointed out to me, Sean, I can't see the cove/water knot in the link you supplied, though I love the way it shows how they're tied.
Incidentally, the dropper loop is almost identical to the blood knot except that in the dropper loop, both 'ends' (in this case a loop) pass through the same side of the twisted section. I don't use it as a loop; I just cut the loop close to the knot so I get a dropper.
Using rig glue or superglue, if you leave a longish 'tag' end, this can be glued along to the dropper end to get greater dropper stiffness, if that makes sense. I think because of the way it's tied it's not as robust as the blood knot if you don't put a dab of glue on it; not really a great hardship. Indeed, tieing a few leaders at home isn't a bad idea if you really want great knots.