Much thanks gents.
It was time to revisit the rear bumper to make it flow better with the body lines. I had already done some of this when I widened it. I added 2 3/8" to the width of the bumper whereas the rear of the car is 3" wider. This helped a lot but it still needed to be made taller to come closer to the rear fender extensions. And the rear fender extensions needed a little trim.
I started with a couple of pieces of 14ga. formed to the profile of the bumper.
Added a V shaped cap and started on the welding and grinding.
More welding, fitting, and grinding to get it close enough for a skim coat of filler. The fender extensions will need filler as well as they did not take to welding very well at all.