As a beginner, I understand running the numbers as far as rent comparables, but also know there's more to consider than that. 

You’re welcome, AllendeAs far as the HELOC goes, if I am understanding correctly, there a possibility for you to use a HELOC on your primary residence, to put a larger down payment on the investment home and avoid mortgage insurance and have positive cash flow from the property?

As far as tips on building capital for a downpayment--maybe get your real estate license? 

SubTo is so RIPE for a "take down". 

The private lending world can sometimes feel like the wild West, but as far as industry norms go I would say that your lender is operating outside of them. 

I wish I could afford California because it is where I live but housing is so overpriced none of the rents wouldl cover the mortgage let alone pull in any cash flow.

Only your personal credit score, photo ID and two months of bank statements are what is asked of you (as far as personal info). 

As far as location’s you will more or less be limited to D.C. and frankly not great areas in the city, there are pockets of Maryland that have them, mainly some parts of Baltimore, a few parts of Baltimore county, Takoma park, Hagerstown & a few parts of the eastern shore but the vast vast majority will be in D.C. 

I'm trying to understand how house hacking is so profitable, putting down so little money, 3.5% or 5% would make for a hefty mortgage payment wouldn't it?

The property management I have is so great to me and my property.