Print out this chart for him.
I have my 400W at 14in from the canopy, so am getting 11,693 foot candles. At 3ft, his 1000W is giving him 4,951 foot candles.
He would have to be at 24in (2ft) with his 1000W, just to MATCH what I get using a 400W at 14in.
A 1000W needs a good air cooling...