What's the best size for an STR?

[Ryan Cummings]

I've been looking at short term rentals in a few different markets. Not quite ready to pull the trigger, but will be in the next 5 or 6 months. I was initially interested in buying a 1bd/1ba condo near downtown Nashville, but as I ran the numbers it didn't look like avg nightly rates justify the investment. It looks like serious cash flow is made once you get up near or above the $300/night ballpark, meaning it requires around a 3bd/3ba or bigger type of property. 

Is my conclusion correct? What are your different criteria for a property when looking at an STR investment?