Hey Derek! There are members here who have fished Volivoli more than me, but for what it's worth, I don't think the GTs there are all-too-fussy.
As with any trip, I would recommend taking a range of lures. Before my visit, Nick said that sinking stickbaits had been successful, especially in the mornings. I ended up only using pencils (my favourites!), and Nick didn't struggle to get follows on anything he threw in the water (blooping poppers; floating stickbaits). All 100-150g. To present these diverse offerings, I reckon a "general purpose" PE8 outfit is sufficient; I always take a spare as well. Obviously, if you've got a strong personal preference for using, say, floating stickbaits, you might want to bring a more specialised rod.
If you like jigging, it's
always worth taking jigging gear! I'm not a huge jigging enthusiast, but I know a group from WA did alright on jigs last year (there are definitely doggies around). I'm sure Nick can confirm.
I would recommend packing a PE3-4 outfit. I concentrated on GT popping, but got into a few tuna when we happened upon bait schools. It's nice to have that light rod ready to go at any moment - you might come across some good YFT if you're lucky. Plus, there's the usual menagerie (bluefin trevs, reefies, etc) to target in the shallows.
Basically, if you want to pop, jig and cast, you can do it all at Volivoli! As they say in the classics, whatever floats your boat
