The "ripples" are due to your setting of 0 for Sample Jitter. Put that back to 1 and they should go away. You also appear to be using an old version as Ray Fuzziness should no longer be an exposed parameter. We recommend running the latest version, in this case I'd guess you are using TG3, so 3.4 would be the most recent update.
To make the clouds more "fluffy", it depends on what you mean by that word. Do you mean softer-edged, or more like a billow cumulus? If you can provide a photo example of what you want to achieve that would be helpful.
- Oshyan