Why is it so important to minimize the size of the tracks? Storage space is cheaper than ever. A 100$ 1TB hard drive lets you store 1,500 CDs in raw format. And the prices aren't exactly increasing, either (at least not over the long term). So, you're really not losing anything on ripping these files in raw format. I would not spend time worrying over which bitrate to use, but rather just rip everything in raw format, and then if availability on portable media is an issue I would just make MP3 copies of these files to carry around on portable media.

@Neil Neyman: The point is that you can control the access right for every single device. So if your cell phone gets stolen, you can revoke its access rights. "But, the thief can use and access my Gmail on the phone right away!" That's why you've set a code for unlocking your phone. You have done so, haven't you? :) An access code might not stop an expert hacker, but it will deter them long enough so you can buy time to revoke your phone's access rights before they can get around to wrecking havoc with your Google account.