I think cf is not as good as gen (of course) or vsf, but it's ok. The clarks is a good solution if any compatible gasket's available. Clarks to me seem almost as good as vsf, judging from pictures as I've never handled a clarks crystal personally. But it does look like there's a small difference in the AR coating being too blue and obtrusive in clarks. Can't comment the edges or clarity overall.
Not sure if the gasket is included with the clarks crystal.
Regarding the whitish gasket in the cf, I suppose it would be rectified if changed... also not sure if the clarks crystal plus whatever gasket is compatible, I'd like to know this myself as well.