I agree nothing new in this research, but I enjoy the map. Once Ewell failed to take Culp’s Hill it was unwinnable by Lee.
When I visited Gettysburg many years ago, I came to that same conclusion, as well as the best opportunity to take Culp's Hill was on day one. Had Ewell maneuvered to the east and then south, while the Union was in disarray retreating through Gettysburg, he may have boxed a sizeable number of them in the town.