I havent tested the script on such a configuration. I'm inclined to believe that it will fail/show errors.
What you need is one fat32 followed by one ext4.
If it's stock rom which you rooted by yourself, it will NOT have ext4 support..
I will be uploading a stock rooted rom for this, on Xda very soon..You can easily use that.
Edit: By the way, the Rom dev mentions on the rom post, whether the kernel supports ext4..Most newer roms do..includingf Lee, Aurax etc..