Digital BW, The Print

So far I have good results with the QTRpc2. I wonder what the 
preference is as Color space. I this Adobe RGB or Gray dot gain 20% 
( or other % ) or Gray Gamma 1.8 ( as for windows printing from 
CS) . So that metamerism is minimal! I normally work from an Adobe 
RGB file, convert with the Imaging factory plug-in, to B&W and end-
up with an RGB file. At this point I have to convert or not?

Thanks for the good work.

Henk