I'd assume that any shop would be able to just remove the glow plug and do the compression test through there so that you would not have to mess with the injectors?
Now... I'd been a while since I've seen any tdi injectors, are they electrically triggered (i.e. easy to disable by just removing a plug) or is there an injection pump with a cylinder per engine cylinder like on the old(er) 2.5L? In that case, you probably would have to disconnect the injector from the fuel rail.
The LRT-19-007 does use a bosche dummy iinjector and is what is called for in the service manual. I am not opposed to using the glow plug port, but don't know what the 200/300 tdi glow plug is equivalent to in the GM/Ford/VW world. Anyone have an idea?