This post shows postally used examples on cover and on piece - and which are far more scarce than the usually seen mint examples that were avidly collected at the time by collectors and speculators.
5,000 sheets went on sale in mid-November 1898 and around half of these were returned to the Lithographic office in January 1899 to be perforated on the Buncle comb perforating machine and then reissued to various post offices. Despite this very short run they were popular with collectors and examples could be seen postally used for several decades afterwards!
So, to sum up; conventional perforations were replaced by a zig-zag roulette - initially with plain incisions, then with black inked incisions, then with both types and finally with standard comb perforations added to make it work!

Mint examples of both plain and black inked zig-zag roulette perforations
On Cover
1898

Plain roulette perforations on what is an apparently 3d commercial rate letter from Brisbane to England on 29 November 1898. Seen in a private collection

Plain roulette perforations on what is an apparently 3d commercial rate letter from Brisbane to England on 29 November 1898. Seen in a private collection
Plain roulette perforations dated Muttaburra 28 December 1898. Seen in the Queensland Stamp Collecting Facebook Group
Plain roulette perforations used on a single rate letter from Gympie to London, England on 31 December 1898. Seen in Abacus auction no 234 lot no 63
1899
Plain roulette perforations used on a country rate letter from Brisbane to Rockhampton on 3 January 1899. Seen in the Queensland Stamp Collecting Facebook Group
Plain roulette perforations used on a country rate letter from Clifton to Gympie on 22 January 1899. Seen in the collection of Dr Andrew Mortlock
Plain roulette perforations block of 6 from the top right hand corner of the sheet used on a country rate letter from Rockhampton to Brisbane on 9 August 1899. Seen in the collection of Dr Andrew Mortlock
1900
Plain roulette perforations used on a double 2.5d rate plus 3d registration letter from Gympie to France on 3 November 1900. Seen on Ebay
1900

1901

1903
Black inked roulette perforations used on a double rate town letter in Wellington Point, Brisbane on 3 September 1903. Seen in Prestige Philately auction no 171 lot no 560
On Piece
1898
San Jose manuscript cancellation dated 7 December 1898. Seen in Phoenix auction no 9 lot no 827. Ex Smithies
Black inked roulette perforations dated One Mile Creek 9 December 1898. Seen in the Queensland Stamp Collecting Facebook Group
1899
Plain roulette perforations dated Mungarr 10 January 1899. Seen in the Queensland Stamp Collecting Facebook Group
Plain roulette perforations dated Oontoo 10 February 1899. Seen in the Queensland Stamp Collecting Facebook Group