That's good to know, I saw a grower on YouTube say they are not much good running at a lower power setting. Due to narrowing of spectrum.
Your right there is a lot of conflicting info out there, the problem is, everyone's grow is slightly different, so there is always exceptions. Maybe it was his make of light bulb that was no good.
I am not saying it's impossible to grow at high temperatures, I just found it very frustrating and stressful being a bit of a perfectionist. So sorry if I am coming over as a bit of a dick.
If you are a new grower it's going to add more stress to your first grow, and a greater possibility of a dissapointment. So I am just trying give you a heads up of possible problems, I encountered trying to do the same thing, I am not saying don't do it. Fore warned is fore armed lol. It's good to have a backup plan.
I was constantly having to re adjust things every day, depending on ambient temps, until I got the air-conditioning set up to deal with all the extra heat, compared to my LEDs I was using, before I got the HPS light.
I would be interested to see a grow run @ 750 on a 1000w light. To know for sure how well the plants do.