Lighting question

I am putting together my first grow room in 25 years. I'm using a 4x4 tent. I plan on using a four site RDWC system. (plant count). My question is which lighting to use. Either a 1000 HPS, or a 600 now and adding a 600 later.
I plan on growing several strains including a few sativa/indica hybrids.

I'd go with a 600 watter... Seems that 600 is more efficient than a 1000.. Yeah.. The 1000 has more lumens but the footprint is large... With your tent size .... I see a dimmable 600 watter being the one for ya..