QTR-Quadtone RIP

I'm new to QuadTone, so I'm just working my way into getting the best 
out of it.  I see a thread touching on soft proofing in Photoshop, 
though I can't find the original source post.  As far as I can tell 
there is nothing in the User Guide or Help on this topic.  Is there a 
definitive document about working with images in PS specifically for 
printing in QTR?  Is it best, for instance to convert images to a QTR 
working space (eg QTR - gray lab) in PS or is that all taken care of by 
QTR's colour managment?