The stuff has a sort of unpleasant orangish cast if untoned. I also have not had very good luck with selenium toner with it due to the aforementioned bleaching. (Kodak RST is compounded with large proportion of ammonium thiosulphate which bleaches the delicate silver image.)
My favorite toner for POP is a thiourea-gold toner. IIRC, I originally found that formula online at unblinkingeye.com in an article on van dyke brownprinting (by White?). I think it is referred to as "Clerc's gold toner." It produces sort of a cool purplish/lavender to on the paper. The Bostick and Sullivan website also has a list of gold toner formulae.
BTW Bob, I'm about to complete the construction of my first Packard Shutter box today so I can use an old 8 3/4" Verito on my Deardorff 5x7 camera and have it synch to a flash. This first one isn't very pretty, but I think it will do the trick. Thanks for the inspiration.
Joe