I think what most call preflower is it being mature and showing sex, roughly 4-5 weeks after popping soil but could vary as much as a week. It will stay like that till you drop light levels low enough per genetics(or age, with its facultative photoperiod). It is then flowering the first night of 12/12. The hormones break down in the light and it flowers again the following night. Doing this succesively creates the flower growth.
I mainly grow landrace sats but have grown lots of tga, sin city bodhi most everything from DNA and everything from og raskal
So have done a wide variety of strains