Our tenants need at least 3.25x the rent for monthly income and cannot have more than 41% of their income allocated to debt that shows up on the credit report (monthly credit cards, car payments, or other monthly obligations) For self-employed applicants we require 2 years tax returns. 

I've got a substantial SDIRA cash position which I've got allocated for real estate and I've been trying to figure out if leveraging is a viable strategy within the IRA.To date, I've interviewed 4 CPAs, trying to find one who can answer questions regarding leveraged assets within a SDIRA.

May increase the allocation to 25% if I don’t get any rentals. 

Also, side note: - would love to interact and get in touch with folks who have a sizable chunk of the portfolio allocated in condos.

She can allocate that cash in any way she wants as long as she purchases at least as much as she sells and uses all the proceeds - to defer all tax.

Out of your experience, how much money would you allocate per unit for a lower-middle class unit that will be renting for around 1500?

The downside to bigger buildings would be, of course, more hands-on management, more tenants means more issues to deal with, more security deposits to put in the right accounts, more rental income to have to allocate to reserve accounts and to track tenant payments, etc.

The Code does not require any particular accounting method however it does require that the accounting system used be in compliance as to Code in being consistent and so as to reflect proper allocations of income and expenses.

Let's further assume that the cost of the property was allocated 80% to building/improvements on the property and 20% to land value. 

Now you're once again dealing with allocations of one unit into residence and business use.