This. I will add: hacksaw is going to leave the top of the steerer slightly crooked. No way around it, even with a guide, unless you are using a reciprocating saw to cut with next-to-no pressure. The less used your saw guide is, the less problems you are going to have, but you are ultimately still cutting with a sawblade that is built to cut into hardened materials, and has kerf that makes the cutting surface farther away from the blade. It drifts a bit, but isn't a practical issue. Make sure you are applying slight pressure towards the main body of the fork to minimize the drifting.
Pipe cutter leaves a more perpendicular top, but will require you to file off a burr on the outside of the tube, unless you happen to have a REALLY expensive cutter (like a Knipex/Gedore) that allows lower pressure while still tracing a consistent path. Obviously, you can't use a pipe cutter for a carbon fiber steerer.
Star-fangled nuts can be installed without a setter, but the setter makes it a generous 95% impossible to screw up. Approximately center the nut, tap the first set of fangles in, and gently align by hitting the side of the setter. Knock in until it hits the steerer tube (sound changes!).
Crown races can be seated with PVC, as above, but be sure to make your tool carefully if the race has integrated seals (like some Cane Creek versions).
