Will there be enough work or guaranteed work to cover 7/24 instead of mining?
No, They explained it earlier, They will use mining as a backup, So when there won't be any jobs running, The software will mine for you. Expect most of the time being spent on mining. An Average commercial would take a mere hour or two to render with 100 GPUs. As I said in my previous post Unless they land every single Animation studio out there, there isn't much stuff to render.
That is precisely one of my concerns about the performance of this project, if your GPUs are not powerful enough for a certain project, almost all the time they will be doing mining not rendering, and if there are too many powerful GPU farms running the competition among them the price of the rendering will decrease. Regards.