If you do them as MP3 files on a CD-ROM format CD (which is sometimes called an MP3 CD) then you have to make sure that whatever player you have will play that. In which case, even at minimum compression, you should probably be able to get it to fit, I think.
But no, redbook is straight minutes, because it's uncompressed audio, and has a completely different format. So yes, I'm saying the latter.