Digital BW, The Print

I know this has been discussed before.  I am printing on various fine 
art Matte papers...Photorag, EEM, Somerset, Moab Fine Art, etc.  I 
would love to know what people like to use to protect, develop Dmax 
and increase depth.  I'm also interested in different surface 
treatments (I don't really want to laminate).  I have tried 
PremierArt Print Guard and like it on glossy and semigloss papers, 
but not particularly well on matte papers.

Any great results on these papers with a specific treatment?

Thanks,

Lou