Here you are:
http://img456.imageshack.us/img456/7774/gg9qn.jpg

As you can see what I meant by slight vignetting is the bit you can see in the corners. Its easily avoidable by zooming in a bit. I was surprised to see you had such an extreme hotspot from yours. Here is a pic of my setup:

http://img456.imageshack.us/img456/8840/setup2ub.jpg

Right now I don't have a set way to hold the lens on so its just taped. And the picture taken of the ground glass were without the macro that you can now see(kind of) in this picture. Here is my lens:

http://img493.imageshack.us/img493/2...nsfront0qe.jpg

If you have any other questions just post and I'll be reading this thread. Hopefully I can be of help.

Thanks Jeff.

I have some ideas, ill try them out tomorrow. Ill report back with my results.

I got some good results with the focus screen from my Minolta slr with the focus aid:
(12:22 AM, room lit only by 80 watt light)
http://www.buysmartpc.com/slr/minolta.JPG

its bright enough to see on my monitor, hopefully everyone else can

I know its blurry, i had some tissue paper hold the screen in place and i could not get the lens to focus because the screen was not at a correct distance.

This is on the same adapter and on the same camera. As you can see the image is evenly lit.The hot spot is barely noticeable, would be invisible with 200 watts.

This proves 3 things:
1) The slr lens is fine
2) Adapter works
3) Camera is able to focus and i dont need any macros.

I still cant get anything better then this with my Nikon focusing screen:
http://www.buysmartpc.com/slr/gs150.JPG

im still trying to salvage the Nikon D screen. I ordered another pcx lens from surplus shed, maybe i can replace the one on the screen.

Too bad the Minolta screen has a focus aid..

I wonder if the Nikon ground glass is a Fresnel...

*update*
I was able to add an additional 80 watts = 160 watts

http://www.buysmartpc.com/slr/gs150minolta.JPG
zoomed out
http://www.buysmartpc.com/slr/gs150minoltazoom.JPG
zoomed in