As far as sanding the chassis, I have followed Mark Payne's excellent advice for a couple years now. One of the things hidden in his information-packed blog is that he does not sand the chassis edge. His reasoning is that by rounding the edges you lose the crisp edge by which to measure/judge ride height. This makes infinite sense to me, so all my chassis are CA-sealed but not sanded.

Haven't split a chassis yet.

Touch wood.

Scottrik