Are your Orion Expanse Eyepieces, 9mm and 20mm, still for sale? I have a Skywatcher 8" collapsible Dobsonian which I believe is an F/6, which is considered to be "fast". From the forum postings I have read, these eyepieces are said to work well with a "slow" telescope. Have you any knowledge about how these eyepieces would work in a 'scope like mine?