Honestly boss if you don't have time to GM you shouldn't run a roleplay in my opinion. It's all well and good but a gm is needed to advance everything unless you give a lot of control to a Co-GM then it will die off quickly. Likewise there will be times where people don't want to post themselves and then you find yourself busy. 

The only reasons my own personal rp's fail is that people fail to see past the boring starts and wait until I can actually spring events into action allowing things to get interesting. I personally find fast paced roleplays distasteful due to the nature of them normally lacking character development at the start and letting people ease into the character. In my mind a roleplay needs a slow start, a rising start, and a quick end just like a book but so many people who do this as a hobby simply don't want to and or don't feel the way I do.

My personal opinion if you're really into stuff trying out 1x1 roleplays will prevent you from having to worry about more than one person and losing the mass with the acceptance that you will be playing with only that one person.

That's just my say and you could completely disagree with me but that's my two cents take it as you will.