I have authored two submissions to federal Redistribution Committees.

So far I’ve done my redistributions relatively manually. I set up a shapefile of SA1s in QGIS with fields for current and projected population, and also current and assigned Division (and of course the SA1’s ID). This makes it relatively easy to reallocate SA1s using selection tools, and maps can be generated by taking unions of the shapes with an OpenStreetMap underlay.