OK, I admit it - my eyes are just getting worse with age. I got the Accu-Matte screen for my 500 CM but I still struggle with focus. I am considering the Intenscreen with a split image aid. However, I can't tell if it also has the microprism ring around it. That really helps when your eyes get as bad as mine. Even with the bifocals.
As far as I can tell the screens with the split image lack the microprism collar. While the microprism is useful in low light or with slow lenses, in general most people experience greater focusing accuracy with the split image.
I strongly recommend two steps that helped me in this exact situation. First, I bought a Maxwell screen (http://www.mattclara.com/maxwell/index.html), and then, with the help of my optometrist, I bought the proper diopter for my Hasselblad. Result? I stopped having focusing issues.
The eye is a living organ that changes over time. A correction today may not be good ten years from now. My eye prescription progressively got stronger as I grew up. Around age 50 the prescription has progressively gotten weaker. My optometrist predicts that eventually I will not longer need correction lens.
Even with laser eye surgery the time comes when the lens is no longer flexible enough to see without reading glasses. Even with laser eye surgery you will end up needing reading glasses for reading and photography.
I don't know if this would help - but I put in an acute matt screen with a 45 degree prism. I could not focus with the waist level finder before at all. I ended up measuring everything to get near (focus wise), because I couldn't see it!
These days I find I get on reasonably well. Even my framing is better than it was - speaking as a 50 year old with very poor close-up vision of course.
Mind you - that doesn't mean my shots are any good of course.