Brush size in Mudbox


I am trying out Astropad Standard. When using Mudbox, it seems to ignore my brush size when using the Pencil. Finger touch maintains the brush size, but when I try the Pencil the circle for the size vanishes and the Pencil barely registers.

I’m new here, so not sure what to expect from Astropad. I’d love to use it—I hate my Wacom tablet.