Simon - the reason you don't read much about the Keyolhu is that most people here tend to opt for the Komodo Dragon which is rated up to PE12. The Keyolhu is rated up to PE10. Considering the Smith rods are able to fish a wide range of line weights as well as cast a wide range of lure weights, I tend to recommend that people opt for the Komodo generally. Most people only get one popping rod so I've tended to recommend one that will give them maximum flexibility.Still, PE10 is a lot so the rod should handle most fish you hook.
I don't have a Keyolhu myself but if I remember correctly, this is the carbon/kevlar rod which Smith claims is for advanced anglers (whatever that means!).
With regard to your spools, PE8 on your 20000 for heavy jigging is ideal. For popping however, you do not need anywhere near this much line. For your 10000 spool, if you fill that with PE8, it will be ample for popping. I am taking PE8 to be 80lb, btw.
What weight line you need depends on the size of the GTs you are chasing and the terrain you are fishing. If the fish are big (20kg onwards to humongous) and you are in rough terrain, you will be obliterated on PE5. I'd recommend you consider PE8 as a starting point. I tend to recommend PE8 as a mimimum for the simple reason that we focus on catch and release - and we want the fish to survive. On lighter line, even if you land the GT, you will run it into the ground and even if the fish is able to swim off, it's shark bait.