Digital BW, The Print

Hi

I am asking the group's advice on this, as I am so new to Epson BW 
printing.

I have been sent a file from a friend who also runs an Epson 7600. 
He currently has Photo Black, and wants to see a print using Matte 
Black.

As he wants a direct comparison, I will not, I suppose, use 
Imageprint for this (unless I want to show him the difference using 
the RIP). If I did, would I send the file in Greyscale, or convert 
it to RGB before sending to the RIP? He scanned in greyscale and 
embedded the profile, by the way.

To send a direct comparison, do I just send this greyscale file out 
from Photoshop in the Epson driver/profile, or would I use my custom 
colour profile? 

Should I print in BO, and if so, how would I do this, as I don't 
know how to do by this method? (I only got the printer a couple of 
days ago and have not yet printed anything with it.)

Any help will be appreciated.

Many thanks,

Ellie