For wacky rigs, an O ring is great to make the bait last... not quite as good for hook up ratio... when you hook the hook to an o-ring the hook is parallel to the worm, thus the tip is not as exposed, so hook up is a bit less.
A weighted worm hook can be effective but not too much weight IMO... 1/8oz weighted hook with a screw in holder is my favorite for weighted, but most of the time, I prefer to fish it with an un-weighted hook... usually 3/0 for 4" and 5/0 for 5".... I don't use the 6" too often.
worm hooks are far more weedless, wacky gives more action for stained water or casting against structure. I def fish them on flouro and WATCH THE LINE!!!!
I wish people wouldn't whore out Colorado waters for the sake of notoriety.