Russel Optics crosshair eyepieces

Does anybody has experienced these crosshair eyepieces, especially the 12mm ?
I know that Russel works well with the optics but as his crosshair eyeppieces have fixed reticles I really don't know if this could be a problem to get a good focus.

Fernando,

I own the 12mm crosshair eyepiece. I use it to get my NX11GPS aligned and that's all. It works very well for that intended purpose. I don't use it for observing and usually when I am aligning the NX11 I am looking at an unfocused star. I am not sure of your purpose for using it, but for the money it's a bargain.

Hope this helps,

Pernel