Hi Damian
i'm not a guru as well, just a very keen angler and fish Mooloolaba frequently.
As you come out of the Mooloolah river, keep an eye out in the bay towards old woman island, tuna do hang around the bay and just depends where the bait are, at times they can feed right close to the shark nets or even close to the surf beaches, whereas some days they will be out wide of the bay. Always keep a lookout for terns and feeding on the surface. sometime you do see tuna feeding without any birds following, it pays to have a drive around keeping an eye out on whats happening on the surface. Try around old woman island as well, over the years have caught really good tuna there. It all depends on where the bait are. If you do see flocks of terns sitting on the water, its a good indication that there has been or will have good feeding happening. Hang around for a while, the birds and fish could just be waiting for the tide to change and the whole area could fire up. I have found that the run in tide good there and lead up or after full moon seems better. Have got fish on run out also, just depends on wind, tide and bait. hope this helps mate.