I'm not fond of the focusing cloth, so I looked around for a loupe that would clear the the top of the toyo's pop-up hood so that the focusing cloth is no longer needed. The only one that I found to do this was Shenhao 6x loupe and it does so by a good couple of centimetres. It's made of metal and has a rubber ring in the front to protect the GG.
My favourite loupe for the 8x10 is made from a high quality slide viewer. I dismantled the slide holding section then taped the loupe into the middle a piece of very thick black paper (in a hole I cut out). The black paper allows me use the loupe without the dark cloth as it usually covers most of the glass.