Not stretching

High bro, Light works with a formula that we call inverse square law. Basicly it meand that the intensity equals the inverse of the square of the distance from the source. For example, the radiation exposure from a point source gets smaller the farther away it is. If the source is 2x as far away, it's 1/4 as much exposure. So when you hang your lights on 20 cm it brings 4 times more light to your plants then when you hang it on 40 cm. So for example you better use 50% on 30 cm then 100% on 60 cm. Your plants will get the double amount of light but it will only cost you half of the electricity. You just need to make sure that the lamp is not to close because then the plants might get heatstress. But there is a really easy trick so you know if your lamp is to hot. Hold your hand under the lamp on the distance that you want to put it above your plants. If it doesn't feel unpleasant keeping your hand under it during 1 minute your plants will be fine. With your lamp I would start on 75% on 40 cm and slightly lower the distance or increase the intensity. When you see the first signs of heatstress (the leaves will fold up like a taco) then put it back to the hight or intensity that you had before. This way you can figure out your sweet spot (perfect distance). Happy Growing! 😋