Ok first things first the times they state are normally estimates it’s more likely to finish at around 10 weeks from my previous experience. Also I normally start counting once they pop there heads up out the soil. As for the lighting I would say when you starting seeing flower pistils swicth to red.. although I never used two bulbs. you can buy dual spectrum bulbs they work just fine
Ps when I said flower pistil I’m not talking pre flowers I’m talking the pistils that start forming where the buds form