Click to enlarge. SO close
The High Brightness mode produces an image in the mid-8000K range (8401K). This is rather cool, but watchable. Don't expect to see any really rich, bright reds though. There is a slight shift to yellow green, but well within what I consider watchable, when fighting too much ambient light. You cannot adjust the RGB settings for High Brightness mode.
No doubt you can push the HC7000 over 800 lumens with a little tweaking. You would have to start with a different mode, such as the Medium mode, which is in the mid 7000K range, and push up green a bit, sacrifice black levels and allow a little crushing of near whites - all standard stuff for squeezing out more lumens.
Bottom Line: The HC7000 calibrates a great movie mode, and a very good "brightest mode" it's just that, it doesn't make it easy to squeeze out a lot of lumens, keeping the HC7000 in the less bright than average range, when it brightest mode.
For those of you familar, this is the post calibration CIE chart: