Ah dang, I had my thoughts and questions all written up nicely and concisely, and was just going to add a few pix when my computer crashed *waaah*
So, again, thanks guys for your insights and illustrations!
And for confirming my fears regarding leakage as well as light efficiency of that HPS too.
Independently of everything else I'm strongly tempted to
immediately (in fact, tis done!) swap that HPS for my MH bulb.
@DonBrennon what you said there reminded me of a factlet I once picked up about the HPS giving off mainly useless yellow light (it was a grow going MH all the way through and explaining why). I definitely was more optimistic about those 150W, hoping it would be closer to "worth" 100W COB than the 50 you're estimating ha!
Gladly! accepting your offer of those 2 CitiCOBs too!
I still have those cheap chinese grunge COBs which I'm not even liking for the seedling cabinet anyway, so I can rework those parts for the Citis (I was going to say provisionally, but hey who am I kidding? The heatsinks are just as grungy as the COBs on em, but they have active cooling in addition, so probably I won't be changing them later on...

)
I now understand that to really get the partition adequately sealed off I'll need to build a proper second ceiling into one side, and maybe even add another vent to extract the hot air without light leakage. Anything else would just be a waste of time and resources.
But I've had a change in plans and will be growing autos in a 2-plant perpetual for the next few months. And given the leaking isn't the only issue, I'm actually all for removing that curtain again, giving the plants that little bit more of space to spread out in, and just letting them run on the same light schedule.
The question remains, which
Taking the autos down to 12/12 right away does leave them with a slightly subpar DLI right when they're developing their buds, plus the large height difference probably cancels out part of the light sharing effect too. So I'm a bit hesitant to flip them to 12/12 just now, especially since I'm really counting on the auto harvest to be a good one.
Independently of light cycle I'm strongly tempted to
immediately (in fact, tis done!) swap that HPS for my MH bulb.
@DonBrennon what you said there reminded me of a factlet I once picked up about the HPS being mainly relatively useless yellow light (it was a grow going MH all the way through). I definitely was more optimistic about those 150W, hoping it would be closer to "worth" 100W COB than the 50 you're estimating ha.
Gladly! accepting your offer of those 2 CitiCOBs too! I still have those cheap chinese grunge COBs which I'm not even liking for the seedling cabinet anyway, so I can rework those parts for the Citis (I was going to say provisionally, but hey who am I kidding? The heatsinks are just as grungy as the COBs on em, but they have active cooling in addition, so probably I won't be changing them later on... lol)
What do you guys think of this:
To put them all on 18hrs for another 2 weeks or so (it shouldn't bother the NLH much, seeing as how she hasn't been able to build up any flowering hormones anyway? Please correct me any time I'm fantasizing!) That would give the autos time to build some nice buds, and compensate for the HID's low light intensity with time till all COBs are in place.
Maybe cut the NLH back by about half and let her re-structure herself. Whereby I am a bit insecure about all the growth down there that would have to grow up to be the new canopy - it's twiggy and stretchy, can that even still be used as basis for a good flowering?
Or I could try and just train her down (especially those supercropped branches popping back up now) instead..
The reason why I'm taking issue with that girl's height is that I went back into my pix archives to check on twig development and instead saw how my NLH clones did quite some stretching
after having gone into flower - and while I do have the height to accommodate those extra 20cm, that'll still be
meters away from the lowest buds, so all that down there is gonna be larf if I leave things the way they are, even with improved lights.
Actually what I'd like to do most is get the NLH going in a way so I can still spread her branches out more after the Cosmic Queens are harvested - give her the whole closet and let her bloom fully. I'd be prepared to postpone the next auto grow in favor of letting the NLH finish in dignity, not scrunched up in the corner as she has become.
Does this thinking ring any alarm bells for you all??
Cheers much!