I'm a big fan of Indagrow 420 lights, but we need to be honest here.
The DO NOT perform anywhere near a 1000w HPS.
In fact, a 600HPS done side by side gives a higher yield.
Not by much, and a 600 actually uses about 650watts, plus added ventilation.
Compare to a 400w MH though, this thing ROCKS.
As for coverage:
These lights cover 4'x2'.
You can get 2 big plants in large pots going really nicely, or you can get 6 small pots all the way to flower if you like that.
They only penetrate WELL about 18". Get a light meter, it's the facts. A 1000w HPS? Several feet further down.
You cannot grow 6' plants with an Indagrow420.
Instead, you can do a great SCROG or something else that keeps plants low.
Should be noted in a SCROG, cut every single bottom branch as they will get absolutely no light penetration below one the screen fills out.
In end, the Indagrow is an awesome machine that SAVES YOU MONEY.
It's $700. But the nicest ballast is almost $200 and the 400w MH bulbs are $120 each and should be replaced every 6 months..