After sanding the curvature with the sander, including changing the angle so that the flange will be formed to 90 degrees near the top and up to 93 degrees near the side, I hand sanded a 3/32 bend radius.

Cut out a strip of material to follow the curve. This first attempt will require bending both flanges down towards the block.

Using the shrinker to shrink up the material.

...a bit too much, apparently.

Getting close.

Tweaking the bend angle with a bending tool.

Ok, that's a rough fit. It has work hardened somewhat...time to re-anneal this piece.