5D III RAW rescale in Resolve?

[zerocool22]

Hello,

I shot some slowmotion with my 5D III RAW ML, and I shot it on 1920x648(50fps) and Magic Lanterns says I need to scale my footage with 1,67. But where can I find this in Resolve (1920x1080 timeline?), I found when I click on a clip there says scaling(and I can choose Stretch, fit, ...) and so on but nowhere where I can put a percentage.

What should be the best workflow for this?

Also how can I add a cinemascope cropmark to my footage in Resolve 2-35-1?

Thanks a lot!