Very dense and/or coarse hair requires a brush with smooth, stiff filaments. The #1 choice here is the Universal. With its complement of four stiff nylon filaments in each tuft, it has the best chance to work through very thick and/or coarse hair.
The Handy and Pocket Nylon would be good choices for shorter hair.
It is possible that if your hair is at the extremes of density and/or coarseness that there is no Mason Pearson that will brush your hair effectively.
If you haven't yet had a look at our full Brush Guide, we recommend doing so.