Ms. Mod, you're correct, I probably should state that this is my opinion only.
If Hulu won't make this significant investment -- King, Abrams, and Franco can't possibly come cheap, at least in terms of profit participation -- only for its premium subscribers, at least initially, then I would question the logic of the Hulu premium model as a competitor against Netflix and Amazon. Indeed, if profit participation is by any chance being used to reduce upfront above-the-line costs and to keep the overall investment at a rational economic level, then it would stand to reason that sacrificing widespread viewership (and thus potential ad-supported monetization) would make sense for Hulu -- i.e., risk low exposure to the project for the chance of getting new subscriber trials.
Plus, for a subscriber (and I am not one), imagine seeing that the King/Abrams is available through ad support...wouldn't that bug the subscriber? Shouldn't subscribers want others to pay so the economy of scale will help the company acquire more content?
One last thing -- I believe there was a project I wanted to see (it might even have been Franco's documentary on Saturday Night Live) and I saw that it was only for subscribers. Thus, given all this, I predict the series will be subscriber-only. If you do find out, please let us know, as I am curious now.