yo guys you're right for HPS....they're surely the real thing for both vegetation and flowering....what you don't really know is that even HPS bulbs have their types as well......there are two types of HPS....the GROLUX and the SHP-TS

GROLUX 400watt HPS = nominal power 400 watt, actual power 430watt...they contain an extra 30 watt of blue light and that makes them real good for vegetation and excellent for flowering

SHP-TS 400watt HPS= nominal power 400 watt,actual power 400 watt..these are oriented for use mainly during the flowering as their spectrum leans on the red and orange side making them a kick ass choice for flowering and good choice for vegetation

currenlty i am growing using 2x400 HPS, one bulb is GROLUX and one is SHP-TS over one 6sqft NFT tray each....i am on vegetation stage on 18/6 at a distance of 35-40 cm from top of plants with good airflow etc.

stick with the 400 watt GROLUX bulb as i think is the most efficient for being able to grow both stages with one bulb.....

one more thing that you must realise is that most, if not all, 1Kw HPS bulbs are SHP-TS type as they are usually used for flowering...

floros are good but HPS are better.....best choice for me (among 400,600,1000 watters) would be the 600watt GROLUX one from Sylvania emitting 100,000 lumens
while the 600watt SHP-TS type emits 90,000 lumens (rich in red&orange)