Compression (or mortise compression) bits work well, and you don't have to use them in one pass, only make sure that the pass depth is more than the up-spiral part, and that the final pass goes through the material.
However, since I tend to be a bit anal about tearing up my spoilboard, I tend to use down-spiral bits and leave ~0.002" - 0.005" skin on the bottom. This can actually be cutout with my knife, then sanded easily. The downcut bits also pack the shavings into the cut, pretty effectively holding the part in place, w/o vacuum and in many cases, w/o tabs. The downcut also keeps the piece down on the table whereas the upcuts can lift the piece.