I fitted a Wide Angle Fresnel (made by Ebony) to my Ebony for use with wide angle lenses - wow - what a difference it made.
One of the best value for money things I have bought - ever - http://www.badgergraphic.com/store/c..._detail&p=1156
The Wide Angle Ebony Fresnel does lenses up to 150mm & they have another standard Fresnel for lenses of greater than 150
I have been told by a friend in the LF Camera trade that the laminated Boss Screen is the best there is - provided you keep the screen below 60C - as above that temp is will delaminate.
I was thinking about doing the Boss Screen as well but have been so happy with the WA Fresnel; I have not felt the need to go further
Naturally, the best screen brightness enhancer is a good dark cloth - what ever flavour suits your needs best.