The Aussie loose rig set up is roughly as follows:
Goldspar 60mm spun tapered mast with 1.67mm wall thickness in the lower section and 1.5mm wall thickness in the top section. (This mast is also used with the tight rig).
In my first boat I had some success using a 55mm Needlspar, but this is much heavier than the Goldspar.
Sidestays were fixed to the mast just below the spinnaker halyard box. The forestay was attached about 180mm below this point. Trap wires were fixed about 50mm above the sidestays.
Sails from UK Burke in Sydney, One Design in Sydney, Hoods in Adelaide, Bob Fussell in Newcastle, or Norths in Sydney.
We used an adjustable forestay and fixed sidestays, with just chocks to control the mast gate. The chocks were rarely touched except in very light or very strong conditions as adjustments to the forestay tension tended to control mast bend.
The mast should be set back in the step so that attaching the sidestays induces some pre-bend around the back of the gate. In order to attach the final stay whilst rigging, the mast will need to be bent considerably. It should not be sloppy without a main on.
As the wind increased we reduced forestay tension and the mast was able to lay back and bend around the gate thus de-powering the rig. Conversely cranking on the forestay straightens the mast, tightens the jib leach and powers the boat up.
The spreaders were pretty standard, pulling the sidestay forward about 25mm and pushing out about 25mm. The lack of rig tension negates much of the effect of the spreaders on the mast.
We had our jib tracks on the Kyrwood boats running across the boat on the thwart that supports the centreboard case. It curves down towards the case, so as the leads were moved inboard the leach pressure increased. Some crews, ourselves included, put a 25mm wedge under the inner end of the track to help open the leach when close sheeted. The leads were rarely moved more than 25 to 50mm. Variations in jib trim were generally enabled through adjusting sheet pressure. The jib height was set so that with forestay tension on the ratio of leach pressure to foot pressure was about 60:40.
An increase in mast rake opened up the leach of the jib and helped de-power whilst decreases in mast rake helped power the jib up by tightening the leach.
A word of warning. It can be very difficult to get this rig to work if you don't have an appropriate mast. We were using a 60mm x 2mm Peelgrane mast which was set up in an identical manner to the Goldspars. The boat felt unresponsive, did not self adjust, and was an absolute dog in light airs. Lowering the sidestays helped considerably, but we were still just off the pace. We replaced this mast with a Spunspar (Goldspar copy) and this put us in the top 5 or 6 in the Lake Macquarie fleet overnight.
If you don't go all the way the results could be very frustrating.
Hope this helps.