QTR-Quadtone RIP

The real question to me now is, what's the advantage to use
Roy's QTR-GRAY/RGB-MATTE/PHOTO profiles?

The QTR profiles came with a Gamma close to 2.5.  So when
Photoshop convert the images, the dark shadows are compressed,
potentially a source of banding for 8-bit files.

We can make QTR curve calibrations with or without using these
profiles (i.e., let Photoshop handles color with the profile
specified as printer color space, or "No Color Management").
We just need to make different curves for each of the methods. 
If we make custom profiles as Roy suggested, since we can only
specify one as the Printer Profile, it is more convenient to make
such custom profiles with "No Color Management" (and the blend
of the curves we want to use without the linearization line),
so that we do not need double convertions (to QTR-GRAY first and
the custom profile later).

I understand we need to standarize the QTR input (so that images
tagged with Gamma 1.8 and 2.2, or what ever, will all print
correctly, since they are always converted to the standard), but,
as a virtual printer, can the QTR's characters be efficiently
modeled in the linearization in the curves, so using the
QTR-GRAY curves is not always necessary, when we make and use
our own custom profiles, and always convert the sourse image
profiles to such and feed directly to the RIP?

Some printing process (such as Richard Lohmann's Hextone) has
a standard input requirement of Gamma 1.8.  My question is
that, with all the QTR's default curves currently designed to
work with the approximately Gamma 2.5 input (in the standard
QTR-GRAY profiles that all the images are supposed to be converted
to before reaching the QTR engine), is the workflow essential
or we can by-pass these QTR-GRAY curves and to use our own
profiles in a single step?

I do understand part of Roy's efforts was to address the
visual difference of matte and gloss prints with these
separate profiles.

Thanks again,
Leping