Aftermarket software like art cam or vectric allows you to define bit size, as far as i-picture just the one listed are the sizes. And in reality there are basically only 3 because the inch sizes have a metric equivalent, the metric ones will require a metric collet i just ordered one.
If you have the 1013 there are other posts on this forum regarding doing multiple passes carving, and basically it does not work out well. You can carve up to 1/4" deep with any of the bits in one pass, but depending on the material I would recommend either regular or slow speed if carving that deep at once. Mostly I use regular speed for everything.