Hi Antaries,
WAC5 is a RAM eater
and sometimes CTD on loading career saves.
It takes very long to load career correctly (about 5mn here) but i found out that not using SH3 Commander helps avoiding CTDs.
As Ivanov said, you should skip full interior, but activate H.sie Supplement for V16B1 Atlantic Baltic Campaign instead of simple H.sie Supplement for V16B1.
Make sure your SH3.exe is patched with the 4GB patch also (if patched with H.sie it should be)
Also make sure before launching WAC5 you don’t have anything running in your PC background (to save RAM)
When it sometimes CTD on loading save, just a relaunch solve it...
WAC5 has the best looking subs and ships, the best visual effects, and great sounds with the Complete WAC5 sounds
Good luck and happy hunting!