Couple notes about disk space and such:
Surface follows the same storage space trend as every other device and HDD on the planet. That means that the 32GB version has 32,000,000,000 bytes of storage.
32GB as calculated by Windows is actually 32 * 1024 * 1024 * 1024 = 34,359,738,368 bytes
So the 32,000,000,000 = 29.8GB in File Explorer.
Then consider the fact that Surface supports reset/refresh. That means there's an image on a separate partition somewhere that enables you to do factory reset. That image is probably at least a few gigabytes in size.
Finally, something you guys with Surfaces have probably not done yet, and something that isn't advertised anywhere - Surface comes with a bunch of language packs preinstalled on it. That's how the first-run experience lets you choose between multiple language packs. The ones you don't use are automatically cleaned up the first time you reboot the Surface. So you might get back quite a bit of space by simply rebooting the Surface for the first time.
Again, if you have any questions please let me know and I'd be happy to answer some more.