For photos indoor (let's say a 65 day strain) I usually let run a full 4 weeks in veg, so add 2 weeks or a tad more to get thru seedling stage... then flip, and the count is on. When growing from seed, your not looking at say GG #4, (the 4 is referring to the original mom being the #4 plant on the original pheno hunt) only GG. So some will run longer & maybe shorter than the stated 65 days in flower. With clones, you find out in a turn or 2 what is the optimal day for harvest. And having 2 rooms, your only concerned about the flowering times.
Photos from seed can be a much more lengthy process compared to running autos.
Yucca powder... something to always have on hand, works great!