When to put auto flower under HPS

Hi I currently have 1. Auto northern lights and 1. Mother of all berry's and 1. Bubble gum. Germinated on new years day so just over a month. In bio bizz all mix soil under 300w cfl and 150w cfl and 2 20w side strips. The auto has started to produce buds.
I know really I should of done either only auto flowers or only normal but I made it complicated :/ and 1 au to and 2 normal.
But my question is when should I switch from cfl to HPS?
I have a 600w digital HPS and 6" hyper fan in a 60x60x200 tent. But I guess I will have HPS set to 250w in that sized tent.

You can switch at any time. A lot of people do the whole grow under HPS. Also, growing auto and photo together isn't too bad as you can still switch to 12/12 when your photo plants are ready or you can veg them longer, taker clones, or make them, bushy as all get out before switching.

2 of my autos started flowering a few days ago. I switched from MH to HPS yesterday.

2nd lateral is good

or once theirs enough mas to justify the cost

and a light FIM I do too at this time

maybe potup

good luck