There's another good leveling app called pinguy which is made just for pinball. You put in the required degrees and it tells you which legs to adjust. Best thing is it has loud callouts of the adjustments for when your on your hands and knees under the table. Once you've leveled the playfield you can also record the glass setting so you don't have to always remove the glass.
As Homepin said, 6.5 is standard, but anywhere between 6.5 and 7.0 depending on personal preference.