It would be easier if you move the files over to the "server" and let MC pick them up there.
The steps below outline what I think would take the fewest steps.
However, there's one important question I don't have the answer to...How do you tag the files and from what machine?
Let's use a couple of example folders:
C:\my music is the C drive on the server machine. Let's say that machine's hostname is SERVER.
This folder will need to be shared on the network with full control access rights. Let's name the share MUSIC for our example.
So at this point from any machine on the network, going to start > run and typing \\SERVER\MUSIC will show the contents of c:\my music on the server.
Now on the headless server, you'll need to VNC into it and start up MC.
Go to File > Import.
Check the box for "Auto-import".
Select the root folder of your music folders, such as c:\my music
This will now start autmatically importing any new files it finds in that folder structure.
Setup portion is now done.
-------------------------------------
Daily grind:
Download songs on your client machine.
Once download completes, move the folder containing the new files over to \\SERVER\MUSIC
Soon after, MC will find them and automatically add them to the library.
Use a "recently imported" playlist to find the new stuff that you haven't tagged yet.
--------------------------------------
Optional step if you're anal about file location:
Highlight the newly imported and tagged files.
Right-click > Library Tools > Rename/Move/Copy files
Change drop-down option to "Rename (moves files if directory changes)
For the Base Path, put C:\my music
Check the boxes for Directories and for Filename
For the rule, use whatever you want, such as [Genre]\[Artist]\[Album]
Same for filename, I use [Artist] - [Name]
Click ok and give it time to work.