Hi Darcal,

I personally use the presets because they are made from actual refraction values. However, to each his own taste. In the example above, I've mixed two different values (common and crown glass) for the refraction with a noise shader. It's a fast way to add variation without a speed penalty that is associated with a bump texture.

Be careful about over setting the render options. The highest settings do not ensure a better render but do guarantee a longer render time. (This is true for all 3D software by the way) Except for special circumstances, basic screen resolution renders like these should take no more than a couple of minutes depending on your system.

Mark