Two days later I uncovered the tuna from the salt mixture, it was firm and ready for the next steps. Rinse the tuna of any remaining mixture and pat dry, place on a rack and then back in the fridge uncovered for no more than 24 hours, until tacky. After that time, its ready for smoking - first I had to dig out the grill.
Once all had been cleared, I removed the tuna from the fridge and placed the rack on a pizza stone and used some balls of tin foil to elevate the rack off the stone for better smoke circulation.
I am hot smoking and try and keep the temperature between 150 and 200 in the grill. The coals are placed opposite the tuna and the pizza stone helps to initally insulate the fish from any heat from underneith - thats my theory anyway. I soaked the apple wood chips and then lay them on the coals, half close the top vent and let it go for 30 mintues. If the smoke amount gets low toss some more chips on. Here it is after smoking.
Overall, I think it came out very tatsty. Some things I would change: This cut of the fish was not as fatty as I would have liked so I think 24 hours would have been enough for curing. With the smoking it overpowers whatever spices you add to the mix, so I might use more spice in the mix next time. Other than that, I was pretty happy with my first attempt.
Now back to the shop - I should have a spirits cabinet update later next week and maybe some progress on the workbench.