Sorry I missed that they were autos. That said, here are some suggestions that should greatly improve your yield for autos.
Lighting
The Viparspectra 600 only draws 296w at the wall, so don't be misled that you've got as 600w light. And if you look at their PAR map in their adds, the only plant that's really getting good photon exposure is the one directly under the middle of the fixture. So given that the fixture is roughly 12" x 15", unless you get 2 of them you're going to have really uneven lighting in a 2x4 tent
Take a look at
https://northerngrowlights.com/ ... 2 quantum boards with a 1050ma driver in a 2x4 space will do great job for you.
or
https://cobkits.com/product/cxm22-passive-light-engine-133mm/ 5 of these @ 3500K with a
MeanWell HLG-320H-C1400B dimmable driver would be very cost effective and far superior to any Viparspectra or other UFO blurple product. Just requires a little DIY initiaive.
Both of these suggestions will generate less heat that the Vipar light and are fine for passive cooling. If you're interested I can give you other options as well
Pot Size and nutrition
Since your goal is to increase your yield ... and I take that to mean greater bud per $$ invested in supplies and utilities, here are some thoughts on grow media and capacity
In a 2 gal pot and soil your plants will basically starve by harvest without nutrients. If you're going to grow in unamended soil, you should be thinking about 2 or 3 plants in a minimum of 7 gal pots for your tent size and even that's questionable for 3+ months of growing time. Even with nutes, I wouldn't go with less that a 5 gal pot or you may end up root bound and have problems with nute uptake before the end of the grow.
Your soil mixture is reasonable, but you should consider a layer of supersoil at the bottom of the pots if you're committed to a no nutes policy. Coast of Maine Stonington Blend or Michigan Mix M3 are 2 off the shelf products that you should consider.
