For example, could you scale and have the security of modest cashflow (somewhere between 2-5% after all expenses, including CapEX are accounted for), if you put 30% down? 

Even if you're still paying for some of the expenses out of pocket, you've most likely drastically reduced your cost of living by eliminating most of if not all of your mortgage, property taxes, and/or insurance.

After expenses the property makes around 7k-10k depending on occupancy, which would be split two ways.

They like solid performers with low LTV.

The other reason is that you need to keep those interest rates low, very low.

I suspect your rent estimate is still low unless your property is a very low-quality rental.

I've included an example below to help illustrate this.So different lenders have different rates (which do vary even for DSCR loans) but these are factors they all consider.See example below:DSCR < 1Principal + Interest = $1,700Taxes = $350, Insurance = $100, Association Dues = $50Total PITIA = $2200Rent = $2000DSCR = Rent/PITIA = 2000/2200 = 0.91Since the DSCR is 0.91, we know the expenses are greater than the income of the property.DSCR >1Principal + Interest = $1,500Taxes = $250, Insurance = $100, Association Dues = $25Total PITIA = $1875 Rent = $2300DSCR = Rent/PITIA = 2300/1875 = 1.23DSCR lenders generally let you vest either individually or as an LLC.

I would like to be able to afford my whole mortgage at 100% vacancy in a disaster scenario, which puts me at buying houses less than 200k at the current interest rates including expenses and insurance.

It's a great way to remove what is your biggest expense (housing). 

Slow and steady wins the race mate.Too many guru's and marketing companies pumping leverage to rookies because they make more money, the more somebody buys.Being patient and using all cash to begin is always safer in the long run.Build the foundation of your portfolio with cash and make it strong.After a few years, look at using leverage for faster growth.And only after you have experienced the true income and expenses of your portfolio and not just paper figures.Cash is KingCashflow is QueenLeverage is the Peasant Just my opinion 🙏