Mark,
Sir Nairne was a local politican and R&A member who championed the idea for "The Modern".
There's no info. - that I know of - regarding the detailed design of the course. What was "modern" about the idea, for one, was the proposed length of "The Modern" -- some 7,500 yards! With the popularization of steel shafts, some golfers at the time felt the Old Course was on the verge of becoming obselete as a legitimate championship venue (sound familiar?!). Moreover, some of the same golfers felt the New and Jubilee courses were sub-standard, and that the creation of another world-class course would attract more traveling golfers to St. Andrews than otherwise.
With regard to steel shafts, there's a very interesting quote in the article attributed to veteran caddie David Cuthbert, who in 1937, gives his opinion on playing golf with a balanced set of steel shaft irons. Cuthbert says, "It's a fu' swing every time wi' a different club, and that canna be ca'ed gowf."
Cuthbert's quote provides a fascinating perspective on how the game was played prior to steel shafts and matched sets.