What's the max salary you would pay Arnett?...

[Preacher Franklin]

He better start hitting the recruiting trail.

 

[vandaldawg]

$3 million and coach in waiting

Never, ever do coach in waiting. Ever.

 

[ThreeDawgNight]

$3M with a sizable buyout.
leave coach in waiting on the table though for future negotiations, and an actual AD in place with a little time to have been around him enough to evaluate him for the actual job.
Keep him happy and make it hard for him to leave. The big schools could overpay and cover the buyout if they wanted but it would still help there and it would take the HC at mid-major out unless he just really wanted the challenge enough to take a pay cut.

Do coordinators usually have buyouts? It seems like neither party would want that: the HC would want the ability to terminate at any time, and the coordinator would want the ability to take a HC job easily.