If you've done it before for the K100D why not try for the K7 too?
You could also try the screen you've made for the K100D and see if it fits on the K7.
Originally posted by RolloR I was also wondering.
I have a bunch of Nikon K3 Focusing screens lying around.
How do you "cut" those full frame focusing screens? They also seem to be much much thicker than my k-x focusing screen.
I've done'it for my KX using one Nikon screen.
As you've noticed they're much thicker than the original one, but focus is spot on (at least on mine body/focusingscreen combo) without using the original shim. (i mean the thickness of the nikon screen was equal to the stock screen + shim).
To cut it i putted the stock screen on top of the nikon and marked the border with a pen.
Then i've used a cutter with a ruler on the guided lines created before (i repeated the process several time so that i could go as deep as possible with the cutter).
The last step was using scissors for the final cut, and sandpaper to refine the edges.
I suppose that something like the Dremel would be better than the tools i've used
anyway here's a link to the discussion (with some pics and feedback on the cutted screen)