I have a P3X 30 inch machine here and I print traditionally and digitally.
I have been printing Cibachromes since the early 80's
Donald. Your question is relevant as the new CPS is basically the old Cibachrome material with a few benifits added in the blue spectrum.It is as brilliant as the older material , in fact I would say it is even better.
Regarding contrast masking I would think that masking would be of benifit for this paper. I will admit that I use photoshop and print with contrast adjusting curves on the Lambda now when using this material.
If I am doing a traditional enlarger hand print I will go to the CLMK or CFK product if the transparancy warrents it.
For those printing on an enlarger and have the skill and patience of making masks I think it is the only way to go and use the CPS paper, (it does have a better colour gamut and contrast)
By the way Don, when I made masks*not for a long time* I would first make a highlight seperation mask that would go on the original before making the contrast reducing mask.I found that by doing this the highlights would seperate out and have more sparkle.
As one can see by using masks the problematic area will be dust as any hint of dust will show up as a black mark on the final print. A mind numbing proceedure if you do not have impecable workflow.
Before photoshop this was the only way to print and there were experts worldwide experienced in maskmaking and colour dodge and burn, now its a very few who will go down this path.