So say like 3-4weeks in you takw tge lower branches that wilk have smalll buds. Then make a clone of thoses since they would finish at the same time but they will also have better light.
I can see what your getting at. The only problem i can see is with root development. Some autos have longer veg periods so just make sure that you take the cutting before the flowering starts so that the roots can get established. I dont see you getting any larger yields since the damage done to the main plant wouldn't necessarily be offset by the clones yields. But try it and definitely post the results.