Mac came out in 1926, and was in the country for just a matter of weeks. He left behind a design for the West; might have designed some holes that are now part of the East; and might have contributed via correspondence to Russell's design of the remainder of the East.
The courses took roughly 4-5 years to construct: it was mostly done by the Club's regular grounds crew, using horse power.
The construction of both courses was overseen by Alec Russell, who was on site virtually every day. The construction work on both courses was managed by the Club's Curator/Super, Mick Morcom (who was a guru, and who is credited with the Sandbelt style of bunkering). Russell and Morcom learnt much directly from Mac during his visit, and tried to honour his design philosophies. Russell was also Mac's Australian partner (a la Perry Maxwell and Robert Hunter); we know Mac and Russell maintained contact.
Russell's stamp is all over both courses. Mac's influence is magnificent and uncontested, but RM doesn't look like any of his other courses. The history of the design and construction of the courses is not well documented. There is contention about whether Mac or Russell was the primary designer of some of the East Course holes on the main paddock (holes now in the Composite layout). A number of people have strong opinions, but we don't know for certain. The genius of RM lies in the combined contribution of Mac, Russell and Morcom: defining their individual contributions is tricky.