Ok...here we go:
How many square feet did you determine can be well lit by this?
What kind of reflector did you use and did you use an adapter so it would screw into a standard HPS/MH screw in?
Was the light run vertical or horizontal?
Distance from Canopy...I saw one grower say he never adjusted the light and just let the plants grow up near it. He started and the light was like 6 feet away. Wondering if you had any thoughts on that.
Any info on reflector, ballast would be great.
Coverage: lights up a 3x3 well, could be stretched slightly by going higher but there's a point at which you'll gain coverage and loose intensity. They're rated for 3x3 and I think that's a good balance between coverage and intensity @20-22" above the canopy.
Vertical: These Sun Systems I'm using are vertical bulb configuration, I've been told there's a slight efficiency gain and read something about that in the Philips documentation, it's slight like 2-5%. The unit is a complete ready-to-go system including the reflector (very high end), T12 vertical socket, and @120v it includes a built-in converter to allow them to run @120v. 240v units are the same less the converter and about $50 less (~$450). Some discussion and looking around at vertical reflectors in the high end, it would be difficult to piece together a better deal if you're thinking of going with a reflector vs. bare-bulb.
Adapters: Depends, they make the T12 socket bulb for vertical fixture/sockets like the Sun Systems. They also make mogul socket lamps which is what Advanced Tech sells, typically used for bare-bulb setups but could be used in vertical reflectors with that sort of socket if they fit in the fixture. If you go with a DIY or piece together a reflector setup you'll have to decide which bulb type/socket/converter depending on what socket comes with the reflector.
Distance: Kind of related to the coverage and I did a lot of trial/error testing in both rounds. 20-22" seems about the best. When I went below that at the beginning (10-12" then up 2" at a time until 22") I got top-canopy leaf discolouration/bleaching, too intense below 20" imo. So far I've run 3 strains and 2 of them, JTR and Blue Dream seem quite happy at 20-22" above the top canopy. I ran the BD in that range through the whole flowering cycle and it got a couple of leaves on the top slightly bleached but nothing to worry about. JTR got nothing really at that height. Myself, I started this current run @30" above the plants as they hadn't been pre-stretched @14/10 like I do if I have the space available in the veg cabinet. They're now at 24" above and expect they'll land right around the 22" mark. The second 3x3 I put in a few days back I left the light at the same height for now as the first 3x3 so it's also about 24" above the canopy, I'll have to move that as these stretch as they'll end up stretching about 8-10" or more. I'll just move them once and guesstimate the final height once they reach about 20" below the light.
Keep in mind I've only run the Sun Systems reflectors, not bare-bulb. There are a couple of folks setting up for bare-bulb runs,
@a senile fungus is one of them and he's going with 2x bare-bulb and a light mover,
see here. Could be slightly different heights running bare-bulb but I wouldn't go too close as it seems 20" is about the minimum height before you'll see leaf bleaching.
If you were using the same light for veg + flowering, imo you could go 30"-34" and get up to 4x4 coverage in veg, then move them down for flowering. They make a 4200k bulb which would be more suited (more blues) for vegging if using the same fixture for both veg+flowering. This is new stuff so a lot of it is just my opinion through testing and observation right now. This run will be interesting as I have 7 strains now in 6x 3Gal, 3x 5Gal, and 2x 2Gal in ~3x6' between the 2 LEC Sun Systems, having so many strains in there I'll get a better idea how each behaves @20-22" above the canopy. I thought I might have more issues with that many strains but so far it's been manageable and with the trellises I've been able to maintain a relatively even canopy. That won't last long as the second 3x3 I put in will end up about 8-10" taller once they stretch. Hope that helps, let me know if I left anything out.