Close lights may reduce stretching, but max light = max growth.
Unfortunately, the size of your plants is due to the disappointing reality of auto flowering plants. Autos need insanely strong lights and "super hydro" growing techniques to get the best out of them. In fact EVERYTHING needs to be optimal for best results - temps, pH, nutrition, light intensity, humidity levels, air exchange etc etc.
In reality, a 240 (claimed) wattage LED is never going to set the world on fire. "Proper" LED grow lights start at around 00 and up.
Hope this helps,......
Organoman.