Brand new to Block paving

[Driveway111]

Hi just looking to see how low the sub base should be from the bottom of the kerb edging to allow sand.....i am using 50mm deep pavers for the edging and will be putting them on a 100mm bed of concrete....i am thinking sub base to 980mm and then that allows for 20mm of sharp sand to be in level with the bottom paver and then further 20 for it yo be compacted down......the edge course will be the same size paver and haunched