Hey bud
For 600 setting = 60cm above canopy
For 750 setting= 70/80cm
1000 setting = 90/1.2m
Space them 1.2m centre to centre of the fixture and no closer than 500mm from ur outside walls
Id go at least 1.2m on 600 if you cant do 400 or lower on vegging also right underneath the lights are...