How should I train my plants?

Hello RIU, My grow area is about 2x3 by 7 foot tall under a 1000w MH, containing 3 kushberry plants. I'm wondering, quantity of harvest wise, what would be my best option as far as training them would be; Let them grow naturally and let them veg tall, or LST them/supercrop/fimming/topping etc, for my specific situation. Pictures can be provided

Scrog for sure. Best bang for your buck in small areas. Or large areas for that matter, if you've got the time.

dude just get rid of your reflector and grow vertical. You can easily do a Vertical SCRog and maximize your space.

Vscrog.
https://www.icmag.com/ic/showthread.php?t=127881

rollitup's finest.
https://www.rollitup.org/advanced-marijuana-cultivation/263751-vertical-growing-24.html

Thanks for the links and info bro. I read someone pulled in 2.5g/watt using vertical lighting. Those are amazing results if true. Right now my grow room is lined from floor to ceiling in mylar and it's extremely bright and reflective in there. It stays room temperature give or take, and my plants are growing bushy. How do you think this matches up, would the vertical setup still stack more light?