Hello Paul,
By the analytics package, do you mean the GoodSuccess add-on? You can check what other information is available there in our documentation
here.
In general the size of workspace data should be more or less equal to size of uncompressed csv files with the data loaded to the workspace.
I don't think there's a simple way for you to check the workspace size out of the box other than the GoodSuccess or controlling the size of data loaded to the workspaces
The workspace power tier is computed for each workspace separately, but they do not depend solely on the size of the workspace, but also on the usage (insight computation, frequency of dataloads and such).
Or which exact limits do you have in mind?