To use co2, your best off to have a sealed room and the lights are air cooled/vented separately. If your exhausting due to heat then your loosing the co2 your putting in. At best, bags are about as effective as you sitting in the tent and breathing in the plants. But it’s not constant and it has a peak output before it tapers off. Same with the 1gal co2 fermenter, not much out put, but you can see it working and refresh it when it starts to slow down.
That said, if you can spare the space for the 2 jugs like that setup, you might as well get yourself a 5gal bucket and a airlock, some starsan sanitizer solution, and a bunch of juice/concentrate to go with the sugar 
. When the yeast is done with the sugar, you have hard cider/wine (depending how much sugar you add, the abv will go up with more sugar, but the flavor won’t really be great at higher abv without some time to age it.
