5-7 hours or more on a 22.5" using a snake (fuse) method. Or you could use a large round charcoal basket like from a WSM and Minion/Soo method. You'd really have to experiment.
So long as the snake doesn't connect and light itself going in two directions at once, you could make a longer snake for more time.
Or, if you created a thicker snake, you'd have more available fuel to burn but would have to shut it down more. And if your kettle doesn't seal very well at the lid or at the bottom vents, your temps might be too high due to more coals running at the same time. And so on.
Actually, that last idea of nearly starving a larger pile of coals as it goes around around is risky. You could snuff it out since more coals = more air required, and it's not as if briquets have thermostats to run "hot" or "cold." They want to run how they run, full-on. Limiting the snake to fewer coals (2x1, 2x2, 2x3) lets them do that, and light the next batch or neighbor. Hope that makes sense.