Well, going on Coyote X's advice, I went and had these two sleeves machines to match the diameter of the axles, and they're thicker than he said was necessary, so that should be good at least. I think the most troublesome bit will be the straightness, though I'm hopping they'll just go in straight and like it.
Here's a picture of the sleeves:
Not the route I wanted to go, but at this point, what other options are there?