For the owner-occupied buyer in our market I usually start with the conversation about drawing the line between utility and investment. Utility being you want a place to live in a certain area because you like it and the subsidized income from the adjoining unit(s) is a bonus. The mathematics can be simple here - mortgage minus adjoining unit(s) projected income. Add any variable expenses (repair/maint/turnover/management software/etc) you wish to account for.
On the other side of the line is strictly investment where we take into consideration the initial 4 investment metrics. 1) pre-tax cashflow; 2) After-tax cashflow (factoring effective tax rate, depreciation and interest expense); 3) After-tax cashflow and principle pay down; 4) Total Return (After-tax + pay down + appreciation-x%). The reality is the bigger pockets perception of maximum leverage (95%, 90%, even 85% LTV) the debt service and PMI kills any potential for cashflows in our low cap market. 5%+ Cash on cash is not possible with this much leverage and anyone who tells you it is, is doing their math wrong. The denominator in the calculation is your "invested equity" ie. down payment for acquisitions. When that number is small (10% of $400k for example), the margin of error is huge. In laymen's terms I like to say with some candor, "you're a microwave away from breaking even". Buying a house hack and expecting cashflow with a low down is not arithmetically possible, especially year 1.
More subjectively I would say, if the low down payment is what is feasible now to be dancing across the utility and investment line. If you can find something with a low down payment, some upside and a monthly out of pocket that is near what is market rent you are heading in the right direction. If you bought a single family home for the same price your monthly out of pocket would be much higher. This strategy is as much as a personal finance decision (utility) as it is an investment. Buyer is unlocking the ability to buy more asset value with a lower monthly out of pocket for single tenant property.
@Brad Hammond made a great point above. The house hack in our market is a lot like what they call a BRRR on BP. Buying the property with low rents, do some updates to achieve market rents and that will force the value as well as sweeten the returns of the house hack. Consider two duplex's next door to each other and are the same size and condition. Duplex A receives $2k a month in rents. Duplex B receives $3,000 a month in rents. When using the income approach, duplex B is worth more money. The stabilization factor of a house hack following the forced appreciation allows the investor to reposition themselves in the asset a few years down the road.
Disclaimer though, valuation of duplex's is convoluted between the income approach and comparable sales valuation methods because of exactly the reasons I've outlined above. Here is an example from a duplex listing in I closed in February. From the income approach this property was probably worth ~$780k in my opinion. Seller would have taken that too. I was using an adjusted expense load from what I considered the "appraisal norm" and a 4.35% CAP. Yes, it was really close in Portland - low cap. I opted to leave one of the units vacant and have the option to market to owner occupied buyers. They bought it for the utility at $820,000 and the appraiser used comparable sales to appraise. The utility of the property to the buyers outweighed the more conventional investment returns and my client made out with an extra $40k. How do you, as an investor compete with buyers like that? Its the same for single family home investors, competing with people who want to live in the thing.
Without diving into illustrations and analysis I have found success with my owner occupied clients by drawing the line between utility/investment and profiling you as a buyer. Are you going to swing a hammer? Then find a value-add/stabilization play. Do you want turn-key subsidized living with a monthly out of pocket that is market, but to own higher asset value than if you bought a house? Then less leverage, more units and turn-key. These are the subjective components to strategy. If you want to dive into the objective ones then a higher down payment is advised. Of course there are exceptions but your findings with the low down payment option is a sticky one.