There are indeed additional parameters. We have added a complete list to Section 2.8. Many are explored to some extent in the results (beta, reversal frequency, domain dimensions, trichome R7 density), whereas most of the physical characteristics of the trichomes are known from published sources (diameter, length, gliding speed, bending modulus), and finally N was simply chosen so that trichomes had a “smooth” appearance.
However, their parameterization of the bending modulus is not acceptable because it leads to an unreasonably large (0.5 metre) persistence length for a bacterial trichome.