Has anybody tried brewing the 1886 Barclay Perkins HSD from The Home Brewer's Guide to Vintage Beer? It stands out as the porter with most speciality malts in the book. Not posting the recipe, but 36% of malts are pale and everything else is brown, crystal, black and amber malts, plus invert sugar. I checked the attenuation and it's 74%. Just seems to break every brewing 'rule' around. I assume that the amber malt was still somewhat diastatic so that might help.