Neil: thanks for the elucidation on Mackenzie's lines. Do you think it was Alex Russell who installed the line at a later date? The two would have had untold discussions on lines. In what eventuated at RM, it's pretty clear that Mackenzie, at least mentally, adhered to the two-line adage. It shows on more than half the holes.
Mark:
Your precied emphasis on how Mackenzie's principles were tied to economy in design and construction, leading to higher productivity, makes sense. One of the points I was trying to make, perhaps not too well, was that all of this was borne of his experiences at St Andrews. The Old Course is all economy; Mackenzie certainly was big on economy.