Nice salmon and great write up. Took me a long time to finally figure out how to cook fish on a grill with out it sticking and tearing apart.
Another trick I learned from the Internet - use a LG 2 prong bbq fork. Put it down through the grates. Slide it over to the fish and gently try and lift it from the underside. If it still sticks give it a little more time. When it's ready it will release at which point you can flip it. Spaculas can really massacre fish especially if it wasn't ready to release yet.