Well, I just fired two PMs in Memphis this year. Both manage hundreds upon hundreds of properties. So that could be considered "successful".
So I don't know. Maybe you just need to put your "shingle" out, at that will be enough. Eventually you will build up a clientele that will stay with you.
Who will your customers be? Out of state or local owners? If out of state, you don't have to worry about the client being able to drive by the properties to check things out. To see if fences are broken down, or the grass is waist high. You can keep them "at bay" for awhile at least. And depending on how far away they are, they're not likely to hop on a plane very often to check up on you . Won't be much cash flow for them to afford many plane tickets. Especially with the loss of rent revenue they experience due to nonpayment of rent by the tenants that weren't screened properly.
Of course, now there is email and such. So expect a lot of pesty emails from them. That can be a reall PITA! They actually think you have the time to keep them updated. You won't because the PM, apparently, is all about "VOLUME". So you will be busy building that up. Besides, you can just give them enuf info to keep them happy for the moment. If the poop really hits the fan, there is not much they can do. You will have a solid management agreement keeping you protected. And the local Realtor Board can't really do much. Besides, it's their investment, not yours.
Sounds harsh, but I'm the kind of jerk you will have to deal with in your new biz. Are you up for it?
PG