Video Exposure: finding the correct ISO setting for video (1DXII)

What is the most accurate way of achieving the correct exposure for video (specifically on the 1DXMII)? Right now, I’m eyeballing what ISO setting to dial in by looking at the LCD screen. Is there a better way of getting consistent exposure levels from shot to shot?

Is there a histogram or a way to show highlight clipping of video files?

1. I use fixed shutter speeds (2x) depending on video mode (24p, 60p, 120p).
2. I do not want to use auto ISO or change exposure settings in the middle of filming

- Low iso as possible for a clean image.
- A shuttersetting with the double as your framespeed: 60p = 120 shutter speedsetting.
- Dialing aperture for exact exposure
- In too bright light, use a ND filter, or as an alternative: do dial the shutter speed.