Marzocchi special tool for tearing down fork?
 

As per the Shiver manual, a special tool R5081AA is needed to split the fork. (Remove the bottom compression valve stuff).

Has anyone got any specs on such a thingy? I will most likely manufacture one myself, there is no chance of getting the real stuff by tomorrow...

It looks like a big hex socket is needed, what's the size?

Not needed. Just use an impact wrench to break the base valve free. The spring guide comes off the damper rod and it can be removed through the bottom of the cartridge like a WP(thanks Les). Easy fork to work on. Only special tool I bought was a seal/bushing driver.