That would have been an awesome GT fight Keith!
Have only fished from a longboard. Would see surface action just past the waves from my old apartment, run down and padlde out. Got bonito, false albacore, bluefish, Aussie salmon and yellowtail. Nothing like the size of your GT though.
But one day after heavy rain was pulling a bleeding bonito towards me, sitting on the board and my legs dangling, when a decent sized something flashed by in the gloomy water. Didn't eat the fish but was enough to make me think maybe pulling strugglng fish towards dangling feet not so smart
Then we had a few nearby attacks and I bought a cheap little sit on top kayak. Legs out of the water! Haven't had it out much while fixing my back.