All I know (which ain't much) is that max heat requires (all else being equal) max airflow. Vents full open. Obviously, the type and amount of charcoal used plays a role, too.
So if you're reading between the lines, one man's all-open might be another man's partially closed if he wants stay stay below HIS max heat.
Back to your original query, I start with bottom vents open and usually vary the flow at the exhaust if necessary, because it's easier to do so there. But that's with a One Touch, which doesn't "encourage" much adjustment down there.
With daisy wheels doing indirect cooking I'm sure fiddling with one of the wheels comes into play ... if I remember to so do and in a micro-manage mood ... to help get that circular flow better (vent underneath food closed, so that cool air can't pull in and mix with heated air AT the food's location.)