The only times I've seen a successful restore of the Google Now Launcher home-screen layout is when it is the default launcher from the onset as the installer goes through it's motions.
Restoring a backup from Titanium Backup does not work.
I've also tried making a recovery flashable update.zip via Titanium Backup but it still won't restore the home-screen layout
adb backup
resp.adb restore
? – Izzy♦ May 18 '15 at 16:03