Template:PortalCharNav/Season Four has 10 cells, and 10 small cells fit fine on my phone (which is the smallest screen I think anybody might reasonably access the site). See Portal:Minor2/Season Four for example. However, 11 small cells don't fit well. So I think when these templates get to 11 (insert Spinal Tap joke here), we should split the small cells into two rows. The smaller row should go on the top, bigger on the bottom (see Template:PortalCharNav/Season Three, which has 13 cells).