I believe spline offset isn't the most efficient way to do this + it offsets on all four sides, and I need only top, left and right to be offset. + That's manual fixing anyways, better off just moving vertices of the spline itself.
What I'm looking for (I believe) is offsetting top, left and right by a set amount of mm/cm. I'm kinda new to RC, but I would be surprised if that's not possible.