This is how I set up flips.......put the handlebars in the stem......turn them over on a flat surface and align them in the same plane. Tighten the stem to hold the bars. Turn them upright and slip on the brake levers. Place the bottom of the drops on the bench with stem hanging off the edge; clamp them to the bench. Align the levers parallel to the bars with the bottom tip of the levers resting on the bench.
This isn't my personal preference, but it looks right in pics......