Fiddly and fiddly.. You could share a directory with the Mac (SMB/Windows Sharing) and then use smbfs to connect to it on the Amiga side. Instant access to the files you have placed there, no need to swap any cards. :-)
Only problem, smbfs is a tad unstable, it might not work at all with your Amiga. :-(
I wouldn't recommend doing a Samba server install on the Amiga, it is more trouble than it's worth + hungry on resources.
