Two different scenarios have recently arisen, and I don't know the proper structure, or if there is any type of standard.1) An apartment investor found an off-market deal directly to the seller, but it doesn't fit their specific investment model (too small - around 60 units), but the deal makes sense for someone who does invest in that size.

This model isn't scalable either.Good luck

@Nelson Lin as others have stated, 80/20 is a good split in a syndicated model. 

Town homes are ok as long as the HOA allows rentals and <$200/mo.Mobile homes don't appreciate.Buy 3/2 houses that will rent after you move.Read the Bullet Proof Rental portfolio paper linked in the fist paragraph of my profile for a business model.

I prefer the buy low, rent high model, so yea, I buy in low income neighborhoods.  

There are some sponsorship groups where this is their entire business model...the student army. 

Go with the worst case scenario when running numbers/financial modeling unless you know 100% what the figure will be.

We do it using the BRRRLO Model in the outskirts where @Bob Okenwa mentioned.We have a meetup tonight about analyzing numbers and 2 trainings at the end of the month on how to buy these types of properties locally.https://www.biggerpockets.com/...https://www.biggerpockets.com/...https://www.biggerpockets.com/...

I would prevent downside scenarios by running sensitivity analyses on my financial model.

Define your business plan (or goal) and then figure out which models best aligns with that plan.