2-10-0 Optimum exhaust rate

[GN.2-6-8-0]

On reading the decoder values of the Bachmann Tsunami equipted russian decapod the programing track find the exhaust rate set at 80 seemed a bit fast but with the correct 4 chuffs per rotation maybe I'm off base . Anyone know what the correct E.R should be. or which sounds best ? 

[SteamGene]

If too fast, slow it down a bit. Drop it down to 75 and listen and see.
Gene