RED has a fairly useful tool on their website that will provide the dimensions of any of their sensors, at any resolution window: http://www.red.com/tools/crop-factor
For what it's worth, the 8K Helium and 6K Dragon sensors have almost the same dimensions, so if you've shot 2x anamorphic 6:5 with a Dragon then 2x anamorphic 6:5 on Helium should give you almost exactly the same perspective.
That said, crop factor confuses so many people, and it gets misused in all kinds of ways. I find it much more straightforward to determine the normal focal length for the format you're shooting.
Based on the dimensions David's provided, by doubling the horizontal dimensions we get virtual capture areas of 42mm x 17.5mm for 35mm 4-perf scope, which has a diagonal measurement of 45.5mm; and 37.84mm x 15.77mm for RED Helium 8K 6:5, with a diagonal of 41mm. The crop factor between the two works out exactly the same as David's calculation, 1.11x, but I wouldn't get hung up on the numbers - I'd think of a 40mm as a typical normal perspective, and from there decide if my normal lens for that movie would be wider or longer than that based on my approach to the story.