In Hawaii, GTs are mainly caught from shore using cut or live bait. There are many GTs taken by shore fishermen for food or tournaments and as a result, I think GTs in Hawaii spend a great deal more time in a bit deeper water. On the other hand, GTs are not often an offshore fisherman's target in Hawaii, so casting poppers or jigging for GTs off a boat might be relatively productive.
I've heard of popping/jigging charters in Kona on the Big Island and there are some jigging/bottom fishing charters in Honolulu at Kewalo Boat Harbor, but I have not yet found any popping outfits on Oahu.
By the way, catch and release seems to be gaining a bigger following in Hawaii and many fishermen do participate in tag and release programs. It's difficult though, to break with the tradition of eating what you harvest.