Library Server replaces the filenames with streamable addresses. They are similar to HTTP internet adresses. Each library file gets a single streamable address. The system cannot possibly work with referenced files like audio tracks from a cue sheet or DVD videos from a VIDEO_TS folder.
The delay issue is releted to the streamabilty. The direct show filters that split and decode video container files on the client PC usually need the see the complete file before playback can be started. In most cases the client must download the file first. AFAIK, only MPEG1 files can be played directly and instantly without first downloading them.
In the current form Library Server is not practically usable with big video files.
However, you can use the shared library system which works fine with video files. A search would probably find more info about it, but here's a simplified explanation:
1. Place the media files in a location that can be accessed through an identical path on all PCs.
2. Import the files to a new library or fix the file paths in an old libary to point to this location.
3. Place the library in a shared location that can be accessed from all PCs.
4. Configure each PC to use this shared library.
Only the first PC will be able to save changes to the library. The other PCs will open the library in a read-only mode. You can update changed library info on the other PCs by reloading the library or by restarting MC. If you want to save changes with a certain MC instance you can close all MC instances and start the desired instance first.