If you truly are serious about investing in the near future, you can always develop a roadmap/gameplan to attain your goal regardless of how financially qualified/unqualified you may be.  

If you have a 60 unit, that is much more attainable because your small changes can have effects on 60 units.

The fact you have made it already is great news and reflects that you don't really need anyone else's input on attaining growth.  

I live in New England near the ocean and have no issue with those temps ( not all makes / models will work)   fujitsu attained sole source certification in 2016 and mitsubishi was close I work with a company that installs as far north as Mainewhlle it is recommended to have a second heat source these newer units can stand alone. check with your local installer for specific models

He's been a great tenant prior to attaining his Section 8 status, and now I consider him my best tenant overall because of it.

Some loose benchmark goals that I've been come up with and that seem reasonably attainable are: by 5 years from now owning between 5-15 income generating rental units, and by year 10 owning between 20-40 units, hopefully generating at least 250-300k between my salary and our rental properties.

If you are successful, you would willingly give me the info you worked so hard to attain, despite the fact that i may use that advice at some point to negatively affect your business by competing with you.

Find what is attainable/realistic for your situation and focus on it.  

Allllllll that being said, you have clear, attainable goals, and a good idea of how you want to get there.

Or am I better off attaining low end deals?