As for the length of eternity, I don't think the concept applies. While we are used to thinking of clock time in terms of finite measurements, it seems to me the idea behind eternity and infinity is a constant. I mean isn't it true that mathmatically, regardless of adding, subtracting, multiplying or dividing infinity is still infinity? You can't exactly have half an infinite amount or one more than infinity or whatever. I think the implication is that if you accept the concept of eternity, you have to then accept your perspective is limited at best. (to go back forever and ever, where there ain't much of anything going on) If anything, the perception of clock time would be an illusion, which is what some other traditions teach.
As for the matter of free will and universal sovereignty, I'm sorry to say that the argument over Job wouldn't really carry. The thing is, again you are playing a numbers game. If there is going to be a group of faithful people and others who are not faithful, where do you draw the line and say this many settles the issue of universal sovereignty? If it's a matter of having exceptions to the rule, there has already been enough I would think.
I don't know, but it seems to me the idea of free will contradicts this idea that the issue can be settled once and for all. I mean if free will will always be there, what's to prevent other people from deciding to be wicked and mess up paradise? I mean Adam was perfect. I vaguely recall something about those people would be destroyed right away, or something, but dag nammit then the second death wouldn't work would it, death was supposed to have been no more..
Maybe my memory fails me, but there is also another issue of just HOW do you know? What constitutes "proof" of a correct way to rule? If anything I think the only solution that fits within that model is that humans have to develop some higher faculties to directly realize what is right rulership. (or actually directly perceive ultimate reality) Even if you look at the world as a lab and use the tools of statistics, the number of factors to control for and possible scenarios have to be up there with infinity. So frankly, if the idea of direct realization is in there it can work, but as we know what is taught is that you just have to believe, and for that matter you're suppose to ignore things you don't understand right now. This is fine, except it seems that it is implied some things you will never understand, which of course may be true. However, if direct realization is what is called for in the way of real proof the only reasonable thing is that you would atleast want to shoot for that through individual development, not stay stupid and accept the words of those assumed to be an authority.