I haven't used a cnat, but have had razors honed on them that was mirroresque.

A mirror finish isn't required. It simply means that the abrasive qualities of the stone is too coarse to achieve that. I have had ugly bevels perform fantastically and beautiful bevels that shave terribly.

The directionality of the striations are based on the direction you move the blade across the stone.

I think you could burnish the stone to get a finer finish. However, this will be a double edged sword. It will slow down the stone.

If you were able to get a mirror finish before, you may be applying too much pressure.