Hi
I would prioritize the product name in the title tag on product pages. Other pages on your site should prioritize the Brand name (assuming you have multiple products from that brand, and a category page for that brand). I'm not too sure prioritizing a SKU would help, since it likely does not receive searches.
Think of it like this; your homepage should prioritize the brand of the website and its perhaps its core keyword. As you drill down into the pages, each page should successfully target categories, sub categories, products etc.
You may want to do some looking at site architecture resources, as they would give you ideas on how to prioritize keywords looking at the site as a whole.
Hope that helps!
-Dan
