Probably the greatest mistake was aiming too low.

I have done everything from a single unit rental for 700k to buildings in the low 9 figures; but most of the properties were in the 5 - 50 million dollar range.I am no longer employed by them and now just do some appraisal in my free time.  

But a % change can be very high when the basis (i.e. denominator) is very low to begin with.  

I know you can get a low down payment home owners loan on a duplex but you need to be sure it will cash flow with a larger loan (higher payment).

Any perspective on which end high or low is more accurate?

Also, if you buy low and have the property rented with cashflow and a good ROI why worry about selling?

That would give me low monthly payments while leaving me plenty of reserves. 

You could rent out the home you're in now and move into the new home to get that low down-payment loan, assuming you have occupied your primary for long enough.

I plan on low balling an offer.

Unless you are highly leveraged and don't have much "skin in the game" as they say, your cash on cash return will be very low.