Yes, and I've done some more reading. There is a wide range of mashing temperatures for corn and the low, medium and high ends of the range correspond to varying degrees of efficiency in the process. The range I believe (based on some reading) used by bourbon distillers in the late 1800's was about 150 degrees F. At that temperature, they got a proper hydration and gelatinisation, and full conversion once barley malt was added. The cooking part of the process toook longer however than if higher temperatures were used. But there were advantages to using the lower temperature, e.g., caramelisation of sugars was reduced. But low temperature cooking - and it seems the cook and mash were one process under Taylor's letter i.e., the grains were added all at once is how I read him - risked bacterial infection. Lime added to vats in the old days to preclude this risk. Also, using an all-backset solution for the corn would provide a lightly acidic ("sour") environment which would discourage action of bacteria and wild yeasts. Today, high temperature cooks are done to sterilise the mash but perhaps in the old days sterilisation was less of an issue if, as we now know, they used all-spent beer to gelatinise the grains.
The question for us I believe is, did the traditional process improve the flavour of the distilled spirit and if so, how?