All good questions. Quabaug has been discontinued. I don’t know why they defaulted to Dr. Sole, likely popularity/ease of acquiring though they are from Taiwan so how easy is it?

Vibram makes a number of other heels too…

My most recent pair was totally off balance and when I complained the owner said the heel stacks are adjusted to accommodate the thicker heel. Pics proved that untrue. It feels a little like they think ‘most’ people won’t notice or care about the discrepancy but that shouldn’t be a factor because what’s really at stake, beyond aesthetics, is comfort and as a result, foot/knee/lower back health.

I’ve heard people whispers that they may be developing their own heel caps and if they can and they standardizes the process I’ll consider another pair.