To answer your question about a bloom enhancer, as you called it, a "yield booster", yes it would definitely be beneficial but it also depends on what your base nutrients are. So let me know that way I can better answer that question for you.
I also wanted to mention to everyone, Flora Nova is a great nutrient however it is a very concentrated nutrient. It is best to use Flora Nova less than half of what it calls for on the back of the bottle. Less is always more.
Typically you want to have between 300 to 600 ppm in the early cloning and vegetative stages. Then you want to move between 600 and 900 ppm in mid veg. In full veg to transition, you want to be between 900 and 1200 ppm.
Also, in hydro you need to remember to change out your reservoir every 7 to 10 days. And if possible have a free standing pump or air stone or both recirculating your water and nutrients so that they dont settle at the bottom of the res.
As stated above the best vegetative light cycle IS 18 hours on 6 hours off. A plant only needs 18 hours to photosynthesize and also needs a resting period (6 hours).
Ideally you stay with your veg formula when you transition to 12/12 until you start seeing bloom sets which is between 5 and 10 days into bloom. Then you stop using the veg formula, change your water in your reservoir, add only a bloom base and if you want a "yield booster" you can start using that at this time depending on which ones you purchase. Your ppm at this time should be between 900 and 1200. At the end of the flowering stage, you dont want your ppm higher than 1500. 1800 at the very most.
Honestly there is no wrong or right way to garden. Everyone has their own successes. Once you have your method down, try not to over analyze yourself because it's very easy to do.
Just remember less IS more and these five key components when your gardening and you will be good to grow
Proper Lighting 20%
Proper Ventilation 20%
Proper usage of Nutrients 20% Fresh water - preferably RO 20%
Your favorite strain 20%