The two agents help minimize the effects of what is commonly referred to as "dual agency."8.

It is a cost effective (although time consuming) way of identifying leads.

Modelling is the fastest, most effective and efficient way to learn.

No idea as to how effective they are and suspect the franchise holders would keep this info pretty confidential.

Was wondering if strategies like direct mailing are effective in this high end of the market...anyone have experience with this?

With the BRRR method if you buy right, hit your rehab budget, and maintain adequate operating reserves, you will not run out of capital.  

Also, the tenants know you have to maintain the property to high standards and won't be shy about demanding repairs constantly.

Mainly because without deep level knowledge those unknown little mistakes add up to big amounts of lost money ( a compounding effect ).The same holds true when when you are an expert in something in that you catch almost all the little things that can really eat into your success with an investment.

Would like to maintain the same quality of SFR as our present portfolio for the simple reason that we never have to worry about the quality of renter in our properties, but our properties have gone way up in price and rents haven't followed. 

I have gotten low as 5% from a very professional management company, but my rents were $2k each and they had several of my properties.My manager does not charge me fees when they go to the property, but their maintainance contractors do if no work was performed.