I have done it.
1000w with 14 watt pannels wont work as well as the other combo.
Its like turning on a flashlight at night then a cars headlight right next to it.
Do you think you will see the flashlight? nope.
I also tried the 400W right next to three LED 14w panels. same deal.
What works with LED is two things. #1 Close to plants like 6 inches #2 any additional
light wont drowned it out like 3 14 watt pannels in the center and 2 150w MH on either side.
I use three with a sunblaze 24" ho T5 that has four bulbs. Here is a shot.
Again, works great for veg but LED ae not powerful enough to flower yet,
If you haven't bought a light yet for flower look into Ceramic metal halide lamps.
Better spectrum, last longer and they run on a HPS ballast so you could always change.