One thing I'd recommend is just adding the tomatoes to your pie direct from the can and seeing how you like the flavor in your finished product. 6 in 1 is a great quality tomato product, and there are some things that just don't need to be improved. I find I like the more 'pure' tomato flavor for the vast majority of the pizzas I make, and find spices distract from the flavor of the tomatoes themselves.
When I do add spices, I almost always used Red November's sauce #2, thread at http://www.pizzamaking.com/forum/index.php/topic,8834.0.html
. It's wonderfully flavorful and spicy and great especially for a more NY-style.