Plant of The Month: 2012 - Creme de la Creme Photos: Dec 2016, June 2017
You can start 12/12 from seed. My current grow is 5 different strains started 12/12.
Since they were fem seeds it isn't necessary to do it from the start, but it was an experiment and it has worked fine so far.
If they are reg seeds it is more advantageous to weed out the males earlier.
12/12 from start might also be good for a more sativa plant like yours to keep its height in check. Hawaiian Snow is straight sativa, right? I know Doc has some huge plants starting 12/12, but his are mostly mixes of sativa and indica (i think).
When I started my current grow I was nervous the plants weren't very big when they started to flower, but if you check my grow, you will see they have grown to a decent size.