I've been doing some thinking along the lines of a variation on what you're doing here, if I may;
I'm designing a modular LED system that allows me to alter the effective PPfd delivered to the canopy at will. Current consensus thinking is that 850 PPfd, give or take, is about ideal for growing cannabis indoors. It can be done with more, but returns begin to diminish. Why? Well, another thread got me thinking... this one talked about how plants actually shut down to some extent during midday because they're getting too much light to process effectively. Perhaps as we do the same indoors, the same thing happens?
So here I am, wondering if a shorter but higher intensity application of light, say as much as 1250 PPfd, might get the best of both worlds.
I'm thinking about lighting half the growroom for six hours at this high intensity, then lighting the other half the same way for the same duration, then off for the usual twelve. I'd ensure that there'd be plenty of light spillover to keep the unlit side from entering its dark phase, and overall energy savings could be substantial vs simply lighting everything all day.
Since we're using higher intensity lighting, my bet is that total yields will not drop by very much and perhaps by less than the 25% energy savings achieved in both lighting and HVAC costs.