I am envious that you have all that space
Im not familiar with that specific product, but it sounds a lot like it has paclobutrazol in it. That shit stops stretch and initiates immediate flowering, and causes cancer. Its a banned PGR in most places. Also very toxic to the liver.If you have to test take a look at Decision by New Millenium, it is suppose to stop stretch per the manufacturer. No test try OG flower hardner, it will stop stretch in a couple days.
Man thats a dope setup. My ass is puckered over here seeing them get so close to the lights though lol. Curious to see how this plays out for ya.