What's up? Over the weekend, while I was working on CM10, I was running into a problem with google play not installing, or so I thought. After messing around for quite a while, I happened to notice that there was only 7.2KB free in /system. So after removing everything I could, including the keyboard, launcher, ringtones, fonts, and more, and removing the 7MB doc viewer from gapps, I still can't get it all to fit. I tried to find the smallest launcher and keyboard I could since the originals take up about 40MB, but even installing replacements so they were installed on /data and then removing the original keyboard and launcher it still wasn't enough. I now have play but only have 8.9KB free and everything still didn't get installed.
So, the moral of the story is that, when you flash a zip in CWM recovery, it doesn't error out or even tell you that you ran out of space. It just skips to the next thing that it can do, like fixing permissions and such, then finishes. More than likely, the problems with which one you flash first is because you are running out of space.
I hope this helps, and maybe puts some things in perspective for those that are wondering why it is not working. I'm gonna see if I can put together a special Gapps that will install to a folder in /data and then symlink everything to /system, but I don't even know if it will be possible.