Scrog distance for 600 hps and 2m height?

Have pots 18 l , cool tube , 6 plants. Coco medium.any suggestion? Thx

I like leaving a half foot gap for plants over 4 feet. Every two feet from there gets a few inches more, depending on bud sites.

As close as possible...
600w

I'm running my 600 cooltube bout 20 inches. Still showing some curl but only around 1-1.5 weeks from chop.