In reply to brora boyan:
I am a big fan of Buffalo. I am also a big fan of Rab Vapour rise. I sold my Buffalo salopettes as I found them just too warm in this country.
I use Buffalo Special 6 (+ Mardale jacket for stops) in winter and Vapour Rise for the rest of the year. Both systems work well as both of them are fantastic at not wetting out and keeping you comfortable.
Are you using the Special 6 next to the skin as intended? It reads as as though you are trying to replace the Special 6 shirt with the Rab guide jacket which would need another layer underneath in my opinion. I suspect that the guide jacket is slower to dry.
Have a word with the knowledgeable chaps at Needle Sports, they know about Buffalo and Rab.