Autos dont really like to be defoiliated because they havd a short grow period which doesnt allow them to recover.
You may want to rely more on grobo supports to keep leaves away from bud sites when growing autos.
However I still think it wise to keep your flower bed/floor from any dragging, spotted or large fan leaves early on.
With that said definitely remove the lowest, biggest leaves!
If you need help just post a picture of the area your getting ready to top and we can walk you through!