Simply side-by-side tasting out of the can is one thing, however when tasting on a pie, I think you should test them exactly as you would use them on a pizza.
It might seem counter to the idea of scientific testing, but I don't think you necessarily want to season them all the same way. You might want to taste each and season such that it's as good as you can get it then make pies and taste the pies blind.
When I make a sauce, I add a little salt and taste. If it needs it, I add a bit of sugar. The amount of salt I add is almost always exactly the same, however the amount of sugar is not. Most of the time, I don't need to add sugar, but some times I do. If I wanted to do a blind test, I don't think it would make sense to add or not add sugar to all the tomatoes for the sake of being consistent in the test. Some might not need any and some might, and I might skew the result by making what would otherwise be the best can too sweet or not sweet enough. Furthermore, if I did the same thing to all the different tomatoes, how would I apply the results to my sauce as I don't always do the same thing when I make sauce.
Every can of tomatoes, even two of the same brand, must be seasoned base on how it tastes. This is how I would suggest testing sauce on a pizza.
Also keep in mind that the best tasting product today may be the worst (or vice versa) if you repeat down the road with can's from different production runs. To have any confidence in your results, you probably should try a minimum of 3 cans of each from different production runs.