I have done it both ways. I wanted to finish these in one operation rather than cut them and then finish with the seat cutter after the forks were complete. Only the one is outside of tolerances (variances?) so I can do something with it and use it on a personal bike for the kids. Chris King sells undersized races for his headsets so, that's another option for personal use.

Same thing here. The fixture is just to hold the crown at the right spot on the steerer when vertical as I am brazing. I like brazing with the steerer vertical rather than horizontal. It just helps the filler flow in the right direction better. I also prep the crown bore and steerer so that the grain of the sanding and filing are in line with the steerer to help the filler flow through better. I flow filler down one side and then slide the steerer/crown up a bit in the fixture so the tips of the finger don't get soldered into the mix. Then I finish flowing the filler down the rest of the circumference.