Before I tackled my
IRS, I bought some 3 tonne stands - can't bee too careful, so I understand that you'd be hesitant.
I used some wood on my diff jack/cradle to buffer the irregular size of the cradle compared to the jack. The whole thing is quite heavy, you can jack up the cradle so that the you can 'hear' that it's taking the weight of the cradle, this should give you confidence that it's supported.
When you loosen the rear two bolts, it'll start to drop under it's own weight too. So if you're unsure back off those bolts and lower your jack a bit, that'll show you how the weight is being taken. The Front bolts through the chassis can be undone when the cradle is supported. For me, the cradle stayed in the chassis at the front and needed a little persuasion to let go. 20 years will do that...
Once the cradle was out, I used an engine hoist to move it around. It's really quite heavy...
The rear bolts thread into a locator pin, it'll make sense once you drop it and can see what I mean. For me these were starting to rust, so be prepared to clean and seal those up.
I took plenty of pictures, so if you can tolerate the loading time have a look at my thread on this forum and those should give you an idea of what you'll see.