depends entirely on the nutes you're running, try and keep your N up during the first few weeks, then switch to PK heavy feeds ( don't neglect N entirely though! )
i'm in new england and haven't seen any signs of sex yet. I know they're female cuz they're all clones, but when does flower phase start up here? I was thinking of starting flower nutes next water which should be wed. or so
Molasses is just a natural additive that helps with its sugars which help break down the nutrients inside the soil and in turn can be more easily absorbed by the plant, it is a misconception that the sugars go strait to the plant, impossible! Molasses enriches the soil.
Answer to your question, use both together, nutes and molasses.
I find PREFLOWERS appear when the plant is about a foot tall, still very young, around about 6 weeks old, usually late April. At this time the plants are still in vegetative growth and will continue growing vegetatively for about another 10 to 12 weeks.
About now, late July/early August proper flowering begins - lots of tufts of pistils at branch tips and along branch shoots.