What you may want to consider is bringing in an equity partner to fund a portion of the deal and have you manage it and find a way to allocate the profits to each party. 

And with more renovations, you will start to get better at ball parking things, but even then you will always uncover items, so make sure you are baking in enough profit, even after conservative renovation budgets to feel confident you won't lose money.

Investors  like us have a smaller profit margin. 

But it could still provide better organization and protection.

We've never had one PM company that we made a profit with.  

You have to vet your tenants well and also I would implement other strategies like seller finance aka rent to own to boost profitability.

I suppose there is a reason agents are doing it but I cannot see this as a profitable endeavor...

My breakdown is about 1/4 Section 8, 1/4 non profits and the rest are regular folks renting .

As you start closing deals, you will need to reinvest your profits into mailing lists and other scalable activities to grow your business.

We calculate gross income as all dollars coming in except taxes.Our clients gross revenue is the room rate (top line) expenses minused out and then they receive their net income.Net profit (or loss) would be then when they subtract debt service, property tax, insurance, utilities, etc.