SpinBase is not a complete ISO, it's more of what you use with Molecule to build your perfect spin. That said, if you want a small CD sized ISO that is a good base to build on, you can use CoreCDX (make sure to remove 'gentoo=nox nox' from the boot line so that it doesn't boot into console mode) or you can use Awesome, LXDE, and E17. LXDE would be the easiest for you to use (because it has a more familiar interface) and all of those fit on a CD (<700MB).
If you have the time, you can use your SpinBase ISO along with Molecule to build your own spin of Sabayon, it's not officially supported, but if nothing else is going on those of us who use it won't mind shooting you some info. There is even a How To written by Joost_Op on the forums if you use the search bar.
Hopefully that gets you started