Thanks, guys. Jitterbug, the only powder I have ever pushed over book max is 800-X. I only do so because all of the book maxes list pressure of 30,000 psi, which is well below the 37,500psi max. I've never gone even a tenth of a grain over book max with Blue Dot or Unique (not that I remember off the top of my head). It seems 800-X has an acceptable over book range, though I may just be asking for trouble.
Taterhead, I think you're right about the 165 Gold Dot being stronger. It has a shallow conical hollowpoint while the 180 has a deep hole drilled down the middle to promote expansion. I will likely keep the tests around book max. While I would love to test them several times (low velocity, medium, and high) these tubes take too long to melt/pour to do it that many times.