For the model pictured below i created a solid extrusion and have knitted a number of surfaces together then used the replace face feature. I built it using this method so that each of the corners of the square form their own junction at their respective corners (instead of creating a radius on my top edges first then attempting this). I now need to add a radius to the outer top edge, and inner faces tappering down towards the centre. I am having difficulty finding a way of achieving this this. Any ideas?

Thanks In advance,

Luke