I did mine with the crush sleeve the last time and I wish I had done the solid spacer. Seems like it's be easier to work with after it was all set up. That crush sleeve works OK, but I have had two loosen up on me (probably due to my other drive line issues I have since solved) and it'd be nice to not have to worry about that. Also, the crush sleeves are kinda one shot and you're done type of thing which I don't dig.
I'm no diff expert by any stretch though.... I have only ever done just mine (with lot's o help) and watched a hand full get done.