Upload & Sell: On
Pretty image. I ca see why you would like a large copy. Whatever you decided, I would carefully check the highlights, soft-proof to makes sure you dont have anything blown out since I think you are close.
Why are you choosing between such very different presentations? Obviously the look of canvas is different from metallic. Are you debating a single image vs the triptych presentation?
Without the question of breaking the image into thirds, I would personally go metallic. You have shimmering sky and water. These elements will dull down on canvas.
Curious what you decide and how it works out. Let us know.