heh
well 1st thing:
you will only see finished files in the "aMule Downloads" folder, the temporary unfinished files will not be there.
you will know when a download is done, when in the amule-gui on the download tab, the progress bar is completly green.
2nd:
your hdd space goes down, when your files have more then 9,98mb downloaded, then amule allocates the complete diskspace for the file. so even if the file maybe only has 50mb complete, you will lose more space on the hdd.
3rd. to make use of your space on the external hdds, you can simple change the path in hte amule-preferences to the location of the external hdds. you can change the temporay directory aswell as the incomming directory. and then both will be unhidden of course. not only the complete folder. just make sure, whenever you start amule, that those external dirve is connected, or otherwise amule will, of course, not find your downloads.
4th to see the contents of amules hidden dir I think you can use the finder of Mac, but nor sure.
and the reason why its hidden. its a *nix standart, that programms settings and prererence files are hidden in the users homedir because you usually dont need to adjust them, or if you have to there are tools.
stefanero