Shoot for 30-33 watts per sq. ft.
If you are set on a cob per foot, then check out the specs for the Vero 18.
31 watts @1.050 amps.
This driver will run 6 of them; Mean Well HLG-185H-C1050A.
If you want to drive them harder, then you can only drive 4 @1.4 amps with the Mean Well HLG series...