How much should we cash flow when house hacking - Single Family home- 4 bedroom/3 bth

[Amity Word]

I have a 4 bedroom ..3 bath home purchased at $275K.

Mortgage is $2210.   It's only 1400 sq ft.  Large deck/huge fenced in back yard/fire pit. 

I'm estimating rooms can range from $950 to $1300 based on what I've seen in the area.

No, I will not live in it.  

Just not sure on average how much one would should expect to profit monthly or to cash flow monthly???

Or which "rule of thumb" applies to the minimum cash flow I should look for?

Separately, what if I only have 3 tenants vs. 4?  Then do I set the rent for each room higher to make up for not having a 4th tenant?