Shared Libraries Memory Allocation

Does anybody know how Flash calls shared library data into another flash movie as far as ordering and memory? In my shared library, i export my assets for runtime sharing. My sharedfonts.swf is 38k. If I have a second swf file that calls the fonts from the sharedfonts.swf, does it open the entire 38k to get the fonts into the second swf? If so, does it load before the first frame, even if I didn’t specify it? I hope I am not too confusing… I just want to know the proper way to optimize data, especially shared fonts. :-/