water stops and swirly bokeh

I just had a question about petzvals and small apertures. Does the swirly bokeh disappear when using smaller apertures? I've been using a neutral density filter for most of my images (10 stop) attached to a step-up filter ring on the back of the lens. This works well except it's a pain in the ass quite simply put. If I were to look into getting a larger one - for my 8x10 2D would it be better to #1 get one with the water-stop or other form of aperture control? #2 Will I loose the vignetting?

thanks!

Dorothy