My largest printer is a Canon iPF8300, so QTR is only relevant for making correction profiles and printing in Canon's B&W print mode (ABW on Epsons). So, whilst not using QTR for print, it's still an important part of my B&W workflow
When I have a file to print I'll convert to the QTR profile and then assign A98 or some other gamma 2.2 space to the file, and then print via the Canon PS plugin (where I can also adjust tint to allow for viewing lighting)
To be honest, soft proofing has very little part in my B&W print workflow. Knowing how my standard B&W test print looks on a paper, along with a good monitor and linearising profile gives me more than enough info to know how a print will look. The test print has a 51 step wedge in it for making the linearising profiles (rgb versions)
The only real guesswork comes in deciding whether to apply a 'lighten' curve to the file before printing, if I know it's going to be displayed in dim lighting - but even that can be quantified to some extent with three versions of my test print on the same paper, with curves applied, and checked on location. Of course, the extra effort for this means it has to be a particularly well paying job ;-)