I use PS to contact print and proof some images particularly when I intend to make both silver and digital prints. I've never thought of using it to establish a starting point for exposure and contrast, I generally know what I want when I go into the darkroom anyway but I think you have raised an interesting point.
I've been doing that lately when I don't have time to go into the darkroom (I don't have a fixed darkroom space, so setup time is a bit of a barrier). The results look different on screen and are only an approximation, but it's a way of "rehearsing" before going into the darkroom. The image I have up right now in the critique gallery is one such image.
I don't actually try to determine actual exposure times, but where I might dodge/burn, or approximate contrast grade to start with, or what lend itself to split-grade printing or require burning at different grades.
The computer and Paint Shop Pro is a good tool for analyzing images for both camera analysis and print analysis. I use one quite a bit in those contexts and nothing more. Every b&w print I have made with the well-known printer has stimulated my desire to get it done in the darkroom instead.
I did one happy task: I made separation prints of a quickly arranged still life and used the computer to produce the full color print. It was quite satisfying but even with the computer registration was difficult and time consuming but maybe not as much as dye transfers. I’ll gladly post the images if you are interested.
Sometimes I have used the PSP program to produce histograms for toning analysis and correction. E.g., I found that Ilford Galerie and Kodak Polymax RC II really are green prior to selenium toning. Lately I’ve been playing around with making b&w targets for film tests with the CRT. Is there enough interest in this sort of technology to elicit an article?
Along the same lines, I use spreadsheet techniques to produce HD curves from density data I obtain with my digital spot meter – maybe another article? I submitted a draft to PT and they accepted it, but I don’t think they will ever publish it – not digital enough . Is there interest here?