"Is there any way to change this either on the live cd?"
I found a way to customise a live cd but not remaster.
Not sure if this is what your looking for but I took a shot at it.
You said;"when I load the live cd, the ramdisk has a size of 16GB."
Any distribution that I have ever installed I have always dedicated 20GB (filesystem /) to the distro and 1GB for the swap. Not sure if your trying to install or if you just want to run this distro-
Also I wasn't sure if you are in a dual boot with another operating system......that matters too-
Hope this helps