Riverdick is right.....don't worry about the where, just toss your lure or bait in front of whatever hotel or condo you are staying at. The glamour predator fish travel all over looking for food and you are as likely to hit one in front of a hotel as you are at a remote beach. Just pick your way out to the end of any likely-looking rocky point and have a go at it. I'd also bring some big poppers, like Williamson jet poppers or a Sebile chugger. The strikes will take your breath away...like someone dropped a 50 pound sack of cement in the water. They'll be tricky to land but you won't forget the experience even if it breaks you off after 30 seconds. Abu......err, I mean 'reefer'...gave you perfect advice on the bait dunking setup

There are GTs on the big island and they'll hit topwaters. Not a high numbers game but they are there. I know a guy who hooked and landed a mahimahi from shore on a big popper too...and you can catch green jobfish (uku) and bluefin trevally (omilu) on the same gear.

Have fun.