Here's the thing, and likely what could happen (obviously a lot could happen)....
Jake has shown signs of being competent, and if he comes out playing well, is there really a reason to play CJ at that point? Which begs the question, why even bother opening this thing up? Is this Bowl game more of an audition for Iowa QB versus trying to win that coveted Bowl Championship?
The issue with Jake is he can't keep up that level of play for more than a half. And it's usually after a first half of just horrible play on his part.
I don't see how you start Jake in this game? We already know what he brings, inconsistency. As i mention above, he leads Iowa to a TD or maybe two, and you pull him and risk taking momentum away and allow TN to take over?
You start CJ, give him the opportunity to take the job then and there. If he cannot get the offense going, then you try Jake. Come back to him in the second half as a way to reboot, and use the same plan.
All this assuming that TN hasn't gone up by 30 points. But this is Iowa football, it'll be a 24-20 game