When preparing for this extended trip, the differing information out there was at times overwhelming, the BEADELL TOURS site proving a valuable resource for Outback tips.
Regarding the old chestnuts of tyre pressures and split rims for example - and after several discussions with Mick Hutton of Beadell's (thanks Mick) - these are our own preferred pressures and speeds for our fully-loaded Troopy, having kept the original factory 16" split rim and tubed skinnies...
Sealed Road 90-105kmHr = 50 front/65 rear (psi)
Good Outback Bush/gravel 60-90kmHr = 35/45psi
Poor Outback Bush/gravel 20-60kmHr = 25/35psi
Dune/Sand country = 15/20psi
Very soft sand = 5/8psi
I must say though, that being on split rims, I'm apprehensive about those lowest pressures, and at the time of writing have not yet dared deflate to 5/8psi... and am not 'planning' to do so.