Thanks all for the very useful replies! I just miss a frame of reference and that's what makes it so difficult to determine my properties. I have to go to practice now (I'm on a ballroom formation team), but I will co-wash again today and watch my hair closely and get some clean, dry hairs to look at them carefully.
Based on the information I got from you all, I'm suspecting I'm probably in between all the 'extremes'. I do have some bumps, but it's not extremely bumpy and you can still slide your fingers down the strand very easily, so I expect my hair is medium porosity. High porosity seems unlikely as I've never done anything to my hair and I haven't used a diffuser or hair dryer for years. Although it could be genetic of course, but my mum's not the right person to check as she treats her hair so differently from the way I treat mine.
My strand research should give me an answer as to whether I have fine, medium or coarse hair. I vaguely remember that they looked at the diameter of an individual strand (under a microsope) when I was checking out high schools and found that it was very fine, but then again, that was ten years ago.
Anyway, I'll keep you posted about my findings!
F - LP - HD - NE
Fine, low porosity, high density, normal elasticity
Natural & CG since 2010
Low poo: De Tuinen Mexican Cactus Shampoo
Rinse-out: Aubrey Organics GPB
Beauty Is Not a Number