@Daniel PattersonDefinitely check out Frank's book like Roy mentioned, but we typically use Cash-On-Cash Return, Cap Rate, and Cashflow after all expenses, renovations, and debt service.

A virtual ssisstant who usually works for you out of this country and will typically be cheaper and good at what you need and you typically communicate with you by the computer.  

They may still put a time line (typically 60-90 days), for their own protection if you decide to buy that property with another agent.

Private lenders typically lend in the first position, not second or third.  

In this area, what percentages for vacancy, cap ex and maintenance do you typically use when analyzing a deal?

I would check with a local HVAC (Hydronic) wholesaler or installer to see if you can still obtain them {be prepared for them to cost almost the same {probably more when you factor in labour} as replacing the entire unit.As for using PEX, I'm not certain if the heat-rated PEX (used for in-floor hydronic heating which runs around 140F) can be used for a boiler and radiators (which typically run around 180F).  

My only concern is being new to the game and not having the experience that they typically look for.

Please share your experienceWhat would typical water/garbage/gas bills look like for 3-4 unit multi family building in Chicago / Cook County / Illinois?

The biggest benefit is, owner-occupied financing typically has much better terms.

Typically this is because a borrower gave the property back to the bank with a deed lieu of foreclosure.