The earlier I try growing (outdoor) auto-flower strains the fluffier my end result. No matter the weather or sun intensity during ripening. I think the plant needs to be very happy all it’s life especially when it decides to start flowering. I think if it’s stressed (cold for example) during flower initiation it will produce less quality flower no matter the care given later in flower.
So I know your talking indoor but it still relates. Keep it happy always. And don’t flip lights till your sure it’s happy in its environment.
Plus light intensity , strain , fresh air, moving air, relative humidity , so on so on so on.
I don’t know if 1000watts is nessesary to make tight buds but it sure will work. I’m sure lots of tight buds came from 400 watt lights as well.
Please don’t take anything I say as truth. I’m still trying myself to achieve tighter buds. Even though bud density really doesn’t matter.