Digital BW, The Print

I have always tried to leave unsharp masking until the last possible step in
my workflow but I am wondering if there are advantages to doing the unsharp
masking before things like the conversion to RGB and applying a curve.  From
people's past experience, where should the step for unsharp masking be
inserted in the following workflow for MIS VM quadtones + Roark curves?

8 bit workflow:

1. Finish all editing and resize to desired printing dimensions and dpi/ppi
2. Convert to RGB
3. Apply VM curve of choice
4. Send to printer

I have been doing it between 1 and 2 most of the time.  I definitely find it
is easier to judge the effectiveness of USM if I do it before the curves are
applied.  Hopefully, someone who knows Photoshop better than I do can make
an informed recommendation.

Thanks in advance,
Doug