Probably better to ask in the 2D Forum about this as I'd think they use it more than those using Poser.

My only suggestion is to get a big one.  The one I had had looked to be a decent size, but it only had a working space of 4 inches x 5 inches and seemed completely useless to me.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi