You have to define the parameters for yourself.

However, back to Enrico's question about the numbers...what would you define as cash flowing for a house hack? 

It’s definately worth the piece of mind.  

Have your terms well defined (cash, cashflow, credit, DTI, job history, etc.). 

Subject To:Subject to Financing Defined.

When a contractor is hired to do a job for a fixed contract price , it is none of the customers business what he pays his subs , how much the material cost , or how much the contractor makes the customer only gets the final bill and all lien releases . " At Cost " is a hard term to define .

I would suggest defining your criteria (2-4 units, renting for xx within these 2 zip codes, under this price point, with X amount of rehab....etc), set-up automatic updates and make a daily effort to do your research and work towards making offers. 

I have learned that the old saying "give an inch, take mile" usually defines these situations.

depends. this money can be a beginning to a lucrative business or a bad decision. you should look at your exit strategy. those strategies should entail making a profit. that defines your risk. more iffy decisions (speculative) should be more about the money you have saved out of your own pocket. we are waaay more safe about that money. lol. why not refinance and pull the money out. why a heloc??

First and foremost, you need to define who does what and who is responsible for what, and how it is enforced when things go wrong.