I have created 3 versions using the sweep technique. Each more preferable then the previous depending on the level of effort required.
1st is a simple sweep that follows the exiting edges of the round. This creates a few artifacts that may or may not be acceptable. In general, they would disappear in tooling.
2nd is the preferred version where the round's edges are extended for the sweep feature.
3rd reconstructs the round geometry and replaces the 50mm normal round with a C2 round feature.
This is the location where the 15 degree line is established