late reply I know, and the guys are pretty right about the abundance of 6-12kg models. We do get the odd oceanic GT, mostly out wide of the harbour but quite a few get caught at night in the harbour by pro jewie fisherman.
An occasional 20+kg trev is hooked in the harbour at random spots, rarely landed as most fidhing here is done on much lighter tackle. I have hooked but not landed several fish that size landbased popping, my 50-60lb outfit getting smoked each time on nearby reef.
For landbased popping the spots are limited, East Pt, Lee Pt and West Pt (other side of harbour) are about the only options and access is tidal. Jigging around numerous wrecks and bombies scattered everywhere. 50lb jigging outfits are more than enough. Land based jigging off the wharfes is very productive for the 6-12 kg trevs.
There are at least 3 species of trevally that get called GTs up here by most fisho's, the most common is light grey and has a yellow tinge on the fins and tail, others are a blueish, tea leaf speckled one, and thirdly is a very grey type with no dots or speckles or colours on the fins.
Just thought i'd put this up for reference for others, even though the info is late.