Sill tanks by all means for the Canning, anything else is overkill. And those I've seen would be vulnerable to rock rash.
I've got the Out of Town Long Ranger, 163 litres. It's taken a lot of punishment, can highly recommend.
A second set of tyres/rims are a good idea. Although you don't need aggressive tyres for the desert, bog standard 235/85s are ideal - high load rating, readily available, tall rather than wide for sand, and AT style tread patterns are usually better in sand.
If however you're out there when the heavens open up & it gets boggy, you'll want those aggressive tyres...
Stereo now by Baja Claws!