I use a Vitorio strainer/food mill http://www.amazon.com/Victorio-VKP250-Strainer-Sauce-Maker/dp/B001I7FP54/?tag=pizzamaking-20
I just blanch the tomatoes a few minutes, and dump in a cold bath (water/ice), enough to handle and then strain it through the Vitorio. It removes the skin, and seeds. It does get watery, so I drain it in some cheesecloth, while saving some of the water for later use. I let the pulp dry some in a container without a lid for a few hours, then add and stir a leaf of basil, salt and adjust the moisture with the leftover water if needed. Then refrigerate overnight as a base sauce.
I use the sauce mainly straight as mixed, or I add garlic, oregano etc depending on the style of pizza in mind.
Organically grown tomato is so much better than store bough fresh. Only issue for me even in San Diego, is that I cannot harvest tomatoes all year as much I make pizza. So I "can" 50% of my harvest in a traditional canning method into " canning jars", or freeze tomatoes for emergency and/or soups, pasta sauces.
I'm still trying different canned whole tomatoes and/or crushed, and definitely searching for bottled type pasta-strained sauces.
I haven't had a chance to try any San Marzano tomatoes grown in Italy, but I grow san marzano 2, san marzano ridorta, costoluto genovese, cuore di bue, red pear from Italian seeds, and domesticated speckled roman, big rainbow, japanese black trifelle, black krim organically. I may not have soil from Mt. Vesuvio, but they taste great.
Straight up san marzano, or plum/paste type tomatoes do not have much flavor vs a beefstake of type tomato even cooked down. Last year, I tried a SM ridorta and big rainbow beefstake tomato once, and adding a good slicer - beefstake tomato adds good flavor. Its so much brighter in "tomato " taste, without all the tin and citric acidiness from can tomato. I'll be trying more combinations with this years harvest for sure!!