Hello
Most LEDs have come a long way in the last several years, unfortunately without a ppfd meter or some other light meter you might not be able to truly say how effective this particular model is. Your average power draw can give you some idea, but really your first grow will tell you a lot. If you're getting 200 average power draw then you could aim at like .5-1g per watt off that 200 number .
With the plants lower levels not getting the best lighting...that'll happen even with good models that have good science backing them. Best thing to do is try LST, defoliate where you can loose some of those biggest blocking leaves, and definitely lollipop the bottoms of your plants as they get bigger.👍