I had similar issues figuring my own hair properties. I think sometimes those of us with very thick hair have a hard time thinking of our hair as fine in texture. It didn't help that as a brunette, of course I could still see individual strands. I think porosity is just as challenging. I've heard the float test is unreliable, and the challenge with running your fingers up a stand of hair is recognizing the difference between a piece of hair that has bumps due to higher porosity vs bumps that could just be due to dryness, or just a strand that has some kinkiness to it's texture (even with fine hair, you'll still find individual strands that can be extremely different from most of the rest of your hair).
When I first started CG I believed my hair was medium-coarse, high porosity. Then I ended up over conditioned in less than a month. So I started adding protein and saw that my hair liked it, so I added more. Despite strong protein treatments and protein heavy conditioners, my hair never showed signs of being over proteined. I finally sent away for the hair analysis and found out that my "medium-coarse" hair was actually fine and my hair wasn't nearly as damaged as I thought- normal porosity and elasticity.

Modified CG since 11/5/11
CLEANSE: CJ Daily Fix, DevaCare No-Poo, CHS Treatment Shampoo
RO: SS Caitlin's Conditioner, CJ Beauticurls Strengthening
LI: SS Repairing Protein Treatment, CHS Silk Leave-In
STYLE: Re:Coil, Curl Keeper, Deva Ultra Defining Gel, Curls Rock Amplifier,Sweet Curls Elixirs Okra Gel and Hard Hold Gel, SS Curl Enhancing Jelly and Firm Hold Gel