Confidence comes with knowledge and action.

I avoid the multi-family market here, so unfortunately, I will not be a good go-to here, but I am confident you will find quality resources and help here on BP.  

Do a few of those and get some confidence, make some mistakes, etc.  

Because they will get defensive if they feel you are pressuring them.

@Hunter Duplantis what @Gino Barbaro said is exactly what I was going to suggest.When you have vacancy is the time to experiment and apply your original thesis.I’m not trying to play Monday quarterback here but, you should be highly confident in where the rents should be well in advance of having a vacancy.That being said, after confirming competition rents on websites (I’d also recommend Craigslist and Facebook marketplace), you should be in alignment there.  

I don't know enough about the start up costs associated with the ATM units but I am generally against businesses that have a short shelf life and here we have one we are fairly confident will be deemed obsolete. 

This is one of the most effective strategies for starting out because it allows new investors to build confidence, raise capital, and transition into long term deals.

There is real estate to buy 24/7/365 when you have built the confidence to do so.

I am confident that I will accomplish even greater things in the future.

The way you handled the owner financing and took on the full rehab speaks volumes about your vision and confidence in the property.