This is a a duplicate of an average comercial operation that I know for a fact can yield on the average 6lbs every 2 months with the right high yielding comercial strain.
Its alot of work to do for one guy with 4 systems like that running as there is an awful lot more that can go wrong I would suggest you get one of those computerized control systems that monitors every part of the system and has alarms and is able to call your cell phone with info if there is any problem. I have seen a couple that are only around $899.