Just going by what Croft Barker says in his book on the 50-70.
However, he was approaching it from the point of view of a BPCR Silhouette shooter, not that of an historical reenactor.
If I wasn't so happy with my Shiloh Military Rifle, I'd jump on the Westley-Richards model just for it's rarity. Only RB I currently own is a very nice Argentine model in .43 Spanish that I 'bubbaed' into a period looking sporter, bobbing the barrel to a mere 30".