For my chestnut Westbournes which are from the benchgrade collection I use Saphir cognac, both cream and wax. Sometimes I throw some Mahogany on the toe cap (1/4 of the time), but only the wax not the cream. For my Hangrade Somervilles, which are also called chestnut (but are a completely different color - much more red), I use Saphir mahogany cream and wax.
Good to know...I prefer Saphir too but he did not have the creams in stock, only the wax. I'll have to add the mahogany to my next Saphir order.