Just implement the Nicehash business model and the project will take off like a rocket.
There are already too many distributed AI blockchain projects (DeepBrainChain, Neuromation, the Leonardo rendering thing etc.) They make it so complicated just to get rich quick without taking any risks. Instead, focus on the actual use case and get something going as quickly as possible. Competition is coming so timing is crucial.
It's hard to do distributed AI due to the bandwidth requirements. I would make things simpler in order to get going more quickly. Set more stringent hardware requirements and let the "miners" deal with it. Look at what DeepBrainChain is doing. They promise a distributed solution but now they are selling high end, pre-built AI hardware and offer hosting. They are basically building a traditional datacenter and letting the "miners" pay for it. All this to buy time and make money quickly. They are selling thousands of these very high end machines (far above 1080 Ti) and the investors are lining up.
Instead, study the Nicehash example. They have made things very simple for sellers of hash power and thus attracted a huge amount of compute power. You could probably just log into their buyers marketplace and calculate the amount of GPU power they have available. Then make some estimation of how much of this is high end enough for AI. All that GPU power would switch to your solution if it would pay more and if it was equally simple to use.