3000 stamps in sheets of 120 is 250 or so sheets - say 60 cancels a sheet takes an hour or two a value. And only 13 vals needed, so 2 or 3 days work for 1 person.
3000 sets? Breckon says 5000 (but less than half sold).
Here are some basic sums, and the numbers presume that the same person or people who applied the CTO cancels also applied the 'Specimen' canceller. 5000 collectors' sets were prepared and distributed. That doesn't take into account spoilage, which there must have been, both in cancelling or separating stamps.
The value of each set of roos was four pounds and nine pence, $8.08 in today's money. In 1907, in the 'Sunshine Harvester' case, which pretty-well established Australia's wage-fixing system for the next hundred years, Justice Higgins set the wage for an unskilled worker at two pounds two shillings a week. By 1913 not much had changed, so a set of those roo stamps represented about 1¾ weeks' wages for a labouring man!
So that one person, or two, operating in the Treasury - and only someone who has worked in Treasury appreciates the full and God-awful significance of that - had substantially more than £20,000 in their hands, quite literally, over a day or so. A truly staggering amount of money at the time. The notion that Treasury would permit just one or two people to be entrusted with this task doesn't gel with me - the more people doing the work the less the likelihood of theft.
There were almost certainly more overseers and supervisors than workers, just like Treasury to this day.