Digital BW, The Print

I had focused on these two models (both discontinued, I want to buy 
one second hand):

X-rite 400: B/W ReflectionDensitometer. 
PDF manual at http://www.xrite.com/documents/manuals/en/400-
500_400_Densitometer_Operation_Manual_en.pdf 

X-rite 408: Color Reflection Densitometer. 
PDF manual at http://www.xrite.com/documents/manuals/en/408-
500_408_Densitometer_Operation_Manual_en.pdf 

Are these good options for measuring B/W quadtone inkjet prints?

According to the 408 manual, it shows measurement data in the display 
for v, c, m and y. But what is "v"? In the manual it is 
called "visual". Is that the same as the "k" in cmyk?
And if so, is that the "density" value I should use when
measuring greyscale wedges?

Or should I go for the 400 B/W Reflection Densitometer?

Thanks again.

I g o r