It depends on how much you need to take off. For larger amounts a small fine toothed saw is what I would use. For small adjustments a rasp can work nicely.
Oops! Sorry.. somehow I missed this response until now
And it's probably a matter of a few mm to get the roof to butt up against a wall. I still haven't bitten the bullet and done it yet, but I'll probably go with the sanding option - thanks for the advice, Tim!
