I don't know what numbers to crunch, nor how to crunch them.
Bourn has an OBA of 339 for his career. In a terrible year, Jackson had an OBA more than one hundred points higher than his BA, and has done close to that every year as a pro.
I agree that Jackson, if he makes it at all, will have enough power to play corner outfield. But that doesn't mean we want to waste his power on the corners, where power hitters are easier to come by. Jackson's greatest value, if he makes it at all, is that he supplies good power at a position where most teams lack good power. I would rather have better than average power in center than average power in left.