Hi, i'm looking to move a couple of imported RKE2 clusters from one Rancher to another - are there any concerns with this? Perhaps some guide or docs around it?

When I was trying to look at this I came to the conclusion there is no "migration" from one Rancher to another, just taking the nodes out of the cluster on one site and importing them anew on another. I missed some steps on the way, but it came back in a working condition. I might just have been lucky, though. Unlikely as that seems.

I'm mostly concerned with preserving the projects and users, how did you deal with that?

With imported clusters, you can simply delete them from one Rancher and add to the other. You'll have to setup new projects and things like that

Ya, that's where I'm looking right now