Safe Margins for Crop Tool

What problem do you see this solving?
I am in the process of selecting images for a gallery show and I need to make the images slightly larger than the mats. I would love to be able to set "safe margins" that would allow me to create an offset within the crop frame, so I could better imagine where the mat would land on the image.

When was the last time you were affected by this lack of functionality, or specific tool?
Today. Currently working on selections for my next exhibit.

Are you using any workarounds or other solutions to achieve your goals in Capture One?
I was eyeballing it, but then I created an overlay in PS to use during the crop. That's working well for now.

Are you happy to be contacted further about this suggestion or request?
Sure.