Density doesn't play as much of a role in things as texture and porosity. This is just quick, not at all scientific, but could give you a starting point until you really do figure it out (you can pay for an analysis through the website I gave you.) If your hair takes HOURS to dry (mine used to be 5-6 even after diffusing for a bit) it's low porosity. If it dries quickly--say an hour or two, it's probably porous. Anything in the middle would be medium, LOL!
My hair is fine and low porosity. It never met a protein it didn't like. I do at least one PT a week and use a lot of products with protein.