Should try to keep it as anonymous as possible, so people can't link names to addresses.
My suggestion? Give an address(since it's necessary) but everyone should have the same name. IE Something like shipping it to:
Graal Notebook
5555 Fake rd.
Faketown, FS, 50505
Then always have the returning address as Pimpsy's. This will also ensure if something goes wrong, it gets back to him. Finally, should try not to reveal(at least on Pimpsy's end) the order of who is getting the notebook, such as who is going to receive it next.