Eg-S Focusing Screen Clarification

The product description for the Eg-S states:

The Super Precision Matte screen improves the ease of focusing when doing manual focus, but is not recommended for use with lenses slower than f/2.8. With these slower lenses, the viewfinder will actually look darker than with the standard Eg-A screen.

Does this mean that if I take an 85 f/1.2 and stop it down to f/4, the viewfinder will be darker than if it had the default factory focusing screen? Or is this side-effect only for a lens where the max aperture is smaller than f/2.8?

Thanks.

No, it would not look any darker(the 85 1.2) because the camera only stops the lens down when you take the picture or use the depth-of-field preview button. When the camera is metering and focusing it is using the lens wide open.
It would only affect you if you use lenses slower than 2.8, such as a 70-200 f/4, 100-400 f/4.5-5.6 etc.

It isn't that much darker either. I use my 100-400 and have no issues at all.