Project Settings Question

[Rick Darge]

When working with a 4k 2:1 clip in Redcine, I used to set my Format tab to 1080HD then I would set my output to ProResHQ 1080. Lately though, I found that setting my Format tab in project settings to 4k 2:1, output to 1080 ProRes, I get a faster render time. In FCP, I have to set a -12 Aspect Ratio distortion in order to compensate for the 2:1 when doing this method.

Anyone else noticing these differences? What's the proper method when using a mac? What's the advantage of the Project settings format tab?