Mate,. Check your additional papers u got from SF.. Every decent light producer deliver a ppfd map, where u can see at what distance what light intensity you have.. When u combine it with the PAR Values we know for the different stages, then u can calculate a distance between plant and light...
Rough PAR values r:
Germination, Seedling:100-300
Veg: 300-700
Bloom: 700-....
Hope this helps, Servus š¤