7/0 .....wow, that is large, but if it works for you, then awesome.
As far as long worms are concerned, I mostly fish ZOOM ol' Monsters and Berkley 10" Power worms, but add others to the mix on occasion. I use 4/0 EWG Gammy's for both and have never had issues. A common myth is that longer worms require bigger hooks. The selection of hook size should be rendered based upon the thickness of the lure, not the length. I try to maintain a hook width to worm thickness ratio of 2.5 or 3 to 1. Basically, I want the hook width to be three times that of the worm. Now, that is purely personal preference, if a 7/0 is working for you, then keep at it, that's what matters.
An interesting point to note though, my average fish size has not increased dramatically using a longer worm. I do catch larger fish more often, but I still catch all of the little dinks as well. I have caught more 8-10 inch bass on a 10" worm than I care to admit. The reason I say that my average size hasn't changed much is because I still catch tons of smaller fish. The bigger fish that I do catch simply don't adjust my average very much when figured in with the multitude of smaller fish. However, before I started fishing with big worms, i didnt catch nearly as many large fish.
Also something that I have noticed with larger worms, is that the fish generally bite the head of the worm first. With smaller worms, I get a lot of torn tails from where the bass will bite the tail and try to drag the worm off somewhere else, but with the big worms the bass generally hit the worm head first. Because of this, I can generally slam the hook home with a big worm on the first tap and come up with a bass, while if I do that with the smaller worms i sometimes come up empty handed or with a torn off tail.
As far as fishing styles, I generally fish both size worms the same. However, I do not fish the 10" worms on drop shots or carolina rigs. I'm not saying that it couldn't be done or isnt a good idea, but I personally haven't had any luck with them presented that way.
If you want to look at some other larger worms or worm-like plastics, check out the Rage Anaconda and the V&M Bayou Giant (14")....its a big bertha worm