This is very true, but to be a good engineering manager, it's hard to fit all the other things in: Representing the team in dreaded meetings, coaching, hiring,

This is very true, but to be a good engineering manager, it's hard to fit all the other things in: Representing the team in dreaded meetings, coaching, hiring, fire, career advice, direction, etc. It is a very fine line to balance. 0-10% is too little. After 50%, you're no longer a manager.