Good Luck with that! Until we see a retail version NO ONE knows what a retail version will have available space wise. The fact that you SAW 8.56gb AVAILABLE at MWC means that is what you should expect. Especially with Samsung, they aren't known for removing stuff, but for adding stuff.
That's why the Note 3 is still the way to go. 3gb ram and 32gb is the smallest configuration.
T-Mobile 32GB - Rooted (TWRP 18.104.22.168)
Galaxy Note 10.1 32GB 2014 Edition
Galaxy S4 (VZW MDK) sold to pay for my Note 3
Droid Bionic - Traded for Note 3
Droid X - Now a WiFi phone.