My grow setup doesn't really compare to yours but nevertheless I have learned some things along the way that I think apply in general and well .. take my advice or leave it lol but...
I also have my exhaust fan on the top of the tent just pointing into the hole on the top (with some ducting), but I don't have a filter. It's legal to grow here now so neighbours be damned lol they can deal with it. The other advantage to running a larger fan then your space needs is that by running it slower it is MUCH quieter (in my experience with the 6" AC Infinity that I am using).
With respect to exhaust though, even though it was a bit of work and required draping ducting all the way across my room I've found that it's basically a must to be venting your exhaust outside of the room, preferably outside of the house altogether through a window or something.
I had an active intake fan but the temps were HIGHER then if I just used passive intakes, and I tested this over and over with my arduino. I'm not a physicist so I don't know why but in my case the negative pressure that results from the passive intake led to lower temps then having an active intake fan. I also made this ghetto filter out of a $3 6" toilet flange, some cardboard, a cheap filter cut to size and some pantyhose and after one grow it's WILD the shit that it picks up, super nasty almost black lol but that shit didn't get into my tent so I'm happy with the diy cheapo filter I made.
I'm still trying to sort out what to do with A/C to draw in cold air to the tent because it get hot in there .. did I mention it's a pretty tiny tent just 2'x4'x5' and havn't come up with much except for maybe a swamp cooler (a decent heatpump or a/c unit is just WAYY too much for the 40sqft space that's in my tent) so I don't have much advice there on how to deal with other then if you can get the ambient temp of the room itself that the intake air is being drawn from you could probably avoid the headache of having to try to remove so much humidity created by having an A/C right next to your intake.
Infrared thermometer as
@Arkos has suggested is a valuable tool to have and they're like $20, it's definitely very informative to have the leaf temp. I also try to take temp/humidity measurements at different locations in the tent (eg. one near bottom near the intake, one at canopy height and one near the top close to where it exhausts), you can buy a 4 pack of temp/humidity meter for like $20 so why not. The data doesn't reveal anything groundbreaking but it has given me an idea on how air circulates when the tent is closed and where there are hotspots. By placing the exhaust ducting at the same level as the light I've had a notable reduction in leaf surface temp and I only figured this out by having a bunch of meters in my tent.
You've probably already got your own but I've attached a VPD chart that I've found to be pretty useful as it shows the desirable values for the different stages of growth.
PS: I have no idea what any of your PS means, what is a Takanime? is that like a tiny nuclear fusion tokamak reactor lol?
jk
PPS: In case you are curious (and I don't know why you would be) my setup is a 2'x4'5' tent with a 6" AC infinity fan at 5/10 setting exhausting; the light is a 400W HPS in a sealed air cooled reflector that has it's own dedicated 230CFM exhaust fan and the air cooled reflector is flanked by 2 70W HLG qb120 boards diyed into a frame of angle aluminum. I've managed to get temps at about 80-85F when I point the exhaust fans ducting near the level of the light which is only about 5F tops over ambient (and that's to deal with 540W of lighting in a 40sqft space) .. before moving the exhaust fan ducting close to the light it was 10+F over ambient. I have 2 intake holes open near the bottom of my tent with 2 of those diy filters. Still working on humidity though and have a raspberry pi sitting here waiting for me to try the Mycodo software which looks amazing (because I don't have to code it myself! lol) for automating my grow hopefully. Wish I had more space because it has been a nightmare trying to dial in my settings.
