We went this route as that is where a large percentage of each of our assets were/are.The ones we have in the SDIRA we pooled our 3 SDIRAs and just purchased outright (no loans).

@Aaron MoayedMost of the buyers I'm working with are purchasing with cash, but yes, a mortgage payment will definitely count against cash flow.Also, that 0.5 was not a percentage: My annual repair estimate is equal to half a month's rent.

Sometimes it can help to convert to percentages. $200-300 per month on a $50K down payment is a 4.8-7.2% annual return.

It's a percentage of the market value. 

A mutual acquaintance has syndicated several deals previously and would be interested to make this happen but from the sounds of it wants me to invest as if it was a normal passive investment through a fund (something I am already doing), making a certain percentage every quarter etc.

They lend based on the asset and they typically have a hard stop at a certain percentage of ARV, 70% for the beginner and 75% for someone with experience.I will try not to tell anyone what to do so attend this event if you want to. 

Would my percentages change because I'll be living in 1 unit?

These are costs beyond the monthly percentage of gross rents. 

It is not uncommon here to see condos that require carpet, or a certain percentage of the floors to be covered with area rugs.  

What percentage of your total assets should go towards a down payment for deal #1?