That's interesting, thanks. You can't go wrong adding older whiskeys as long as they don't dominate, and sometimes adding a high proof whiskey brings a certain clarity or "focus" to a blend. I think the whole point of this kind of drink is its complexity. There is a certain quality a great bonded or single barrel has, its singular character and force; a blend works at the other end of the spectrum.
Both are valid expressions of the whiskey idea. I think too Mike that in the 1800's when those heavy glass decanters sat on the back bars, even if they bore the name of a distiller or a merchant's brand, they would have contained vattings of whiskeys and maybe (depending on supply or the probity of the saloonkeeper) not always straight whiskeys. There would have been a variety of tastes, always changing. We don't know at this far remove, but maybe that was regarded as positive or as a typical feature of decanter whiskey. Maybe each saloon, or some of them, had a house approach to it, or relied on a merchant who did the vattings for them: probably that was more common and merchants would have needed to do that to create an interesting, consistent product.
I know too "barrelhouses" sold direct from the barrel as many grocers and saloons did too: there would have been a variety of practices.
Just recently I was reading about the history of rum in Trinidad recounted at
http://www.triniview.com/sugarcane1.htm. Like everywhere the distilleries have declined in number but a few survive and are well-established. The account states that before WW I, each sugar refining factory had a still. (Originally these were pot stills, and later, wooden column stills). Around WW 1, merchants bought aging stocks of rum from the dozen pr so distilleries and combined them to sell at wholesale. It was common for the retailers to sell the rum in a type of carafe called a "petit quart". Probably they dipped them in the barrels containing the combined rums. The account said sometimes the retailers did the blending and that some unique blends were produced by the "haphazard" combining of the rums. However I also believe this practice encouraged the development of systematic blending (highly advanced today in the rum-producing countries).
I wonder if that 1920's blending was really haphazard. It surely was in some cases. But in others I think people would have said, um, this is a young fiery blend, add some of that older treacle-like rum. Or, put some cane syrup in that barrel, don't make it sweet but just to soften it. That other barrel there has a strong rank taste, mix it with that sweet dark rum there to tone it down, etc.
Probably Scotch whisky blends developed methodically from similar practices by grocers in Scotland who were obtaining supply, often intermittently, from different sources. Johnnie Walker was a grocer, so were many of the people whose names adorn today the well-known blends. I think the first vatted whisky (all-malts), Vat 69, was created by Jonathan Usher, an 1800's Scots merchant.
This doesn't mean a blended or vatted whiskey or rum is superior to a fine bonded or single barrel whiskey or batched straight bourbon or their rum equivalents. Each type is different and valid on its own terms. The blended and vatted ends of the spectrum can be appreciated for the complex, unique flavours that result.
Gary