QTR-Quadtone RIP

The documentation indicates that I can use an acv curve from
Photoshop, but I haven't a good idea how to do this... and the
documentation is simply not at all clear. Do I just build an arbitrary
grayscale (i.e. single-channel) curve, then save it and import the
file?  Or do I use a curve with 4 channels (e.g. quadtone curveset)?

I'm just getting started with B/W printing, and QTR seems so far to
work much much better than the kluged ultratone curves that would be
used under Photoshop.

Thanks in advance for any help.
DRK