I understand the concept , and have done basically the same thing
with shrimpboat trash for tarpon. I suspect what works best for
tarpon may not be best with tuna.
Do you fish with rod in holder and strip line with 2 hands or hold the rod and strip with one ? complete freespool or clicker on ? Engage drag quickly or slow? Please describe what a strike looks like and exactly what you do next.
We do the same thing when we fish big bluefin tuna behind scallop draggers. If you are not experienced tuna fisherman, I don't recommend complete freespool because you can get bird nest on your reel if you don't act in time. Give enough slack line in the water and just move the lever drag to strike smoothly (some people like to move drag to 1/2 or 3/4 of strike initially) when tuna takes your line. Before you take rod out of holder crank as fast as possible. When you feel tuna are secured, then you take rod out of holder and fight.
When you hold your rod while chunking, you feed your line with your one hand. Give enough slack line so that your bait doesn't drag. I prefer complete free spool instead of crickers on when I hold my rod. I put my thumb slightly over the spool to prevent from backlashing when tuna takes line. When tuna takes bait, I usaully decide when to move the lever to the stirike based on the speed tuna takes. It can be two or three seconds or it can be 5 or 6 seconds. In this process you just put your thumb slightly over the spool so that tuna doesn't feel any registance while preventing from bird nesting. I saw even experienced fishermen lose too many fish by giving too much time with clickers on.
Whether you use J hook or circle hook, don't try to set the hook. As tuna run, they usually hook themselves and crank as fast as you can when rod tip goes down. Once you are secured, then put your rod on your fighting belt and fight.