And how to do that? I mean re-partition without needing to back the data up?

As far as I understood from some quick googling, the partition-table isn't structured the way that I can snip 4GB off MyDocs and add it to /home/ ? Or am I mistaken?

Hopefully I'll be able to fiddle with all that tonight. I do need to do that from a natively installed Linux-box, correct? VM won't suffice? (no problem though, I have an old laptop around)