I can't think of any resources for you, though I was in a similar position over a decade ago, learned something very valuable (to me) and would like to share.

I can't think of any resources for you, though I was in a similar position over a decade ago, learned something very valuable (to me) and would like to share. Be very careful about investing time into operations, especially standard operating processes when you're still in startup phase. Scale will fuck with SOPs like nothing else and if you hit a flashpoint, you'll likely discover that SOPs actually handcuff your early employees. A far better use of your time (at this stage) would be selecting/training staff to think more like a founder, demonstrate initiative and think their way through fucked up messes. Metrics are relatively useful, but you've got to be very careful not to look at them as absolute measures of productivity and rather look at them as more of a sign of an upcoming problem. If you focus too much on productivity, there's a very good chance that you'll optimize away the employees who actually belong in a startup.