Hardcore height to paver

[Driveway111]

Hi i have added the edgings now and need to install the sub base. my question is how low the sub base should be from the bottom of the paver...is 30mm enough or is too shallow.....i have also added kerb stones at the front of the drive and haunched them so the first paver will be pretty much sat on concrete with around 10 to 20mm of sand underneath it...is this ok

[lutonlagerlout]

ideally you should aim for 25-40 mm of grit sand
problem is if your haunching is too high it may compact differently to areas with more sand
we try to ensure the same amount of sand all the way so any settlement will be even
cheers LLL