Tricky. I'd focus on making the troika as strong as possible. Head Coach and the Coordinators and I wouldn't get lost down this rabbit hole. If you devote your mental resources to gaining an advantage here (minimal impact) you'll lose grip on strategies that affect the actual on the field.
I know Infinity has mentioned it and I've never truly took one gander at it but positional coaches movements (guess Ima get acquainted with the graph charts). One thing to note is with positional coaches you're at the mercy of the unemployed talent pool, therefore, you can't just go poof and have highly rated coaches. (you're looking at 60+ overall rated guys) I suppose this is where targeting certain attributes per the positional coach comes in...
It's interesting.