Low porosity would certainly make sense. It would explain the obscenely long drying times, the crispiness, constant dryness and horrific tangles.
Plus it would explain my frustrations that I've never done anything "harmful" to my hair - never use driers, straighteners, mousses, dyes etc etc, yet it's still in terrible condition.

Going to experiment with avoiding protein. Should I give my hair a good wash beforehand to get rid of the previous build-up?