Dan,If you are going the BRRRR route, couple things.

If it is you, stop and add it to the rent if they want to continue to use that method.  

., method of installation, you must purchase the material before 3 p.m. on a Tuesday, etc.)

It rented for $1950 per month and I refinanced it for $156,000 six months later - a classic BRRRR.

Have income high enough to meet their threshold for the properties that you are buyingIn terms of getting multiple mortgages with smaller down payments, you could do the live in BRRR method.

Are there any better methods than direct mail?

Its based on County, method of payment, down payment of and so forth...The app works well.

Obviously you would probably get better terms financing it with residential, but I am curious if the rules of forced appreciation still come into play when financing through this method. 

@Kelly S.If owner financing is not an option, you can research other methods like lease options.  

They can be installed in various methods whether is be fully adhered or mechanically attached but the best part about them is they have heat welded seams which are the strongest point of the sheet vs. an EPDM seam which is an adheared seam and can fail if water ponds around it.