Brightscreen for D800, anyone tried it?

Just resurrecting this thread to see if anyone else has experience to share?

As far as i know there is no katzeye for d800 but there are options listed on brightscreens...

Has anyone ever tried sending a d800 with a third party screen into Nikon UK or otherwise and asked them to swap the screens? Is it something they will do or will they refuse? I am worried about this shims business since accuracy will be super important with 36mp. The d800 is made for some nice fast zeiss glass but the focusing screen really doesn't cut the mustard...