welcome to the site, Travis. When you have a moment, it would be great if you could amend your user name to your real name. We request that on this forum as we feel it adds to the integrity of the posters and the forum - and it's a littl emore personal to boot!
If you're planning on getting into heavy GT fishing, then yes, it is unlikely that the Stradic 6000 and 50lb braid will suffice. There probably are areas where you could extract a decent fish on that tackle but much of the areas which GTs inhabit off the Queensland coastline are decidedly unfriendly. In addition, there are many of us who believe that much heavier lines are the way to go as it gives you the ability to land a fish quickly and before it is completely exhausted. that way, we give the fish the best chance of survival.
A Stella 10000FA and a Shimano GT rod would be a great outfit. If you intend to fish 80lb TF XP, you will get about 170m onto a 10000 spool which is sufficient (just). This will give you a fighting chance against a decent GT. Personally (and other can feel free to disagree), however, I'd recommend 100lb line but the problem with this is you start to get a little underdone with a standard 10000 spool. For 100lb braid (assuming TF XP), you'd probably be better off with a 16000 spool or a Yumeya 10000D spool (unfortunately, very pricey). Your other option is to go for a premium Japanese line like Varivas GT where for the same diameter (PE8), it'd be 100lb.
A price of $650 to $675 is amazingly good. The current Stella FA will be superseded in a matter of months but the new model will be much more expensive and you can buy the current 10000FA with full confidence that it will do the job well.
Good luck - if you do manage to land a big GT on this gear from a kayak, we'd love to know!