I recalled reading a post on the PMQ Think Tank where a poster, who was a pizza operator, addressed the issue of trying to fathom the basic NY style pizza sauce. This is what he had to say on the subject:
Remember when it comes to sauce and dry spices... less spice is better. Many people have tried to duplicate NY Style pizza sauce.. they even dumpster dive for secrets and there are none. They always over-spice their sauce. Take 2 cups of Full Red pizza sauce and add a cup of water to it (maybe a bit more). This is a thin sauce for the same reason the dough is a moist dough.. the high heat will boil the water out of the sauce.. too thick of a sauce and you will have tomato paste under your toppings and it will be sickeningly pasty on the edges. Add 1/2 tsp of oregano, 1/2 tsp of basil, 1/4 tsp ground black pepper and 1/4 tsp of crushed red pepper, 1/2 tsp salt, maybe 1/2 tsp of sugar if you think it has too much of an acid bite to it and finally 1 tbs of the fresh grated romano cheese. Stir and let set an hour or better yet overnight.
With a 6-in-1 sauce, you perhaps wouldn't want to add additional water unless you like a really thin sauce. The other ingredients can be adjusted to taste. If you'd like, you can drain the 6-in-1s to get the texture you want, but as you will see when you get the 6-in-1s, they are fairly thick to begin with.
In my case, I use the 6-in-1s right out of the can, without draining. Sometimes, when using a seasoning such as the Penzeys pizza seasoning, I may heat up the seasoning with a little oil in a sauce pan, usually along with garlic, and then add the 6-in-1s. I cook the sauce a bit to marry the flavors but not to the point of boiling, and for as short a time as possible. There may be a slight reduction of water content, but not much. I then refrigerate the sauce for use later, usually the next day. I might add that I have become very fond of the imported dried Greek oregano, which scott r introduced me to, as well as the Sicilian wild oregano. Sometimes I use just that herb with the sauce, with nothing else, not even salt. It makes for a nice, clean, fresh taste. It all depends on the taste effect you are trying to achieve. For a Sicilian style, I might shoot for something more robust.