OK, when you tell someone "Here's a better more efficient way of doing things" and they respond by basically saying "I'm aware of that but I'm not interested in changing things just yet", at this point you've said your piece, gave your advice, now its up to "HIM" to incorporate (or not) it into "HIS" grow. He apparently believes he has things under control and that's "HIS" right, no need to get offensive or rude about things, come on guys, its his cake, let him slice it and eat it how he wants to, lol. I'm sure after he harvests this round he will setup things better for the next round, one thing I will recommend again for your next round is to put the glass in those hoods and hook up some ducting and an inline fan, I know you said you heard something about the lenses blocking like 10% of the light, that may be true but with the lenses and ducting your able to remove around 70% of the heat the bulbs produce enabling you to get the hoods a LOT closer to the the plants which in tern penetrates much better into the canopy, not to mention gets more of the light & radiation onto the plants. OK, Ive gave my advice and now your welcome to do what you will with it, good luck and post some pics.
Oh, by the way you know that when a plant flowers it starts using the sugars in the leaves for bud production so yellowing of the leaves is quite normal, you see it all the time in flowering pics, so you might not have a N deficiency, or you could and I don't know shit, lol.