You can try to use the method -mtta in Freearc if sorting becomes a tedious job, most people don't know that Freearc does have wav file compressor but it only works if the audio files are not archived or in another container. Plus handing over files from that forum is against the rules.
Edit: I remember once having problems using msc on Left 4 Dead 2 which forced me to used Freearc's built in wav compressor.
left4dead2_dlc3\sound:
-mtta
Code:
Compressed 4,778 files, 1,315,603,487 => 649,582,676 bytes. Ratio 49.38%
Compression time: cpu 69.56 sec/real 142.00 sec = 49%. Speed 9.26 mB/s