I think this is a great idea. I have one concern which I will share with you.
You should introduce new writers to POB, you should earn money off of this leg work that you do... but at some point, you should cut the writers loose to be their own POB'er. That is likely the only way to ensure longevity of your project.
As a contractor, working for a middle man is always a good foot in the door, but once I find out how much money he is getting from "hooking me up" I get mixed feelings. At that point, I quit and try to be my own man. This will ultimately happen with your magazine as well. If you can keep bringing in good writers, make money off of their introductory post(s) and then onboard them to the platform and repeat the process, it is win-win-win.
You will have my support on this.