I just measured the bridge height on my '60s ES330, which currently has a B6 on it. The Bigsby pushes the strings upward away from the body compared to where they would be on a trapeze so they're not directly comparable. The problem with the B3/B6 is that it was designed to work with guitars that have a true archtop bridge as you'd find on an ES175 or Gretsch, so the Tunomatic screwed into the top is a challenge.
