Never had a circle hook thats been bent open and closed again break or fail in any way. Less chance of twisting up, it's nice knowing that swivel is there when the tide starts running... those baits, whatever it is a guy will put on like to spin like an airplane prop don't they!
The only way to get the eye open is with a vice, bolted to a work desk. Once the Barrel Swivel is installed, use the Vice to open the Circle hook up just a bit, it's not necessary but once you add a giant bait, that extra bit might be the difference to a Halibut that is Mouthing and Spitting without you ever knowing it.