Here’s my secret, I have mephisto autoflower since July 3rd that are double yours in size and starting to flower. I don’t even use a tent till it’s 5 weeks old, I use a closet for all my plants seedling to vegging stage. I use three 300 w Home Depot lights…. 3 of them together using a little clip on desk light and when they get taller I move the lights up more on the next shelf which is higher. This will shoot your seedling and veggie str8 up, this is the most important stage for me because it will allow you to have monsters. When they are like 4 to 5 weeks they should be nice and tall plants. I did the same mistake on my first grow, I didn’t lower my lights and I have adjustable lights.. I just assumed they were strong enough, they finished decent just no where as nice as my yields after this assured method. Long story shirt I’m able to put each seedling or two under a 300 watt bulb, and it shoots straight up better then the grow tent (cuz you can control the lights easier) by the time pre flower hits you can put the plant in the tent and not worry about weak lighting and all. Best of luck