The CD-R's I use (Maxell CD-R, 700MB, 80 Mins) have a "safe" limit of 700MB. I use Nero to burn CD's (for PC's, haven't tried burning any for my CD32 yet) and if I use overburn (burning beyond the "safe" point) I can add a few MB's of data to the recommended storage level. This can be dangerous to both the CD and the drive, and any data overburned is said to be much less reliable than the "safe" limit.
As far as Amiga's go (unless you are using Amiga One, or Pegasos?) 700MB's is more than enough space for storing files
Regards,
Lonewolf10
