I've done that, sliced tomatoes into 1/2 inch thick rounds then quartered the rounds, then dried them in a dehydrator over-night so they were pretty dry.

By the time you make the sauce, boil up the onions, garlic, what ever, the pieces have pretty much disintegrated. End of the day, thats a lot of work for not much benefit.

Its a lot easier to add tomato paste to the sauce to thicken it up, and not boil it as long.

I should note that we make a sauce with dried tomatoes, using red wine vinegar, water, olive oil, crushed garlic, and dry oregano. Fill a quart jar with the dried tomatoes, use about 1/3 each oil, vinegar, water, and fill the jar, let sit overnight to soften, then food process with two-three cloves garlic and 1-2 teaspoons oregano until smooth. Strong flavors, but really, really good on pasta or spread on toast.

Your dried tomato sauce recipe sounds great! I like strong flavors. :)

For future reference, why not grow varieties that have much less water and gel? I have a sun dried tomato business and I want large, few seeds, drier than the Sahara tomatoes. For sauce, all I grow and use is Costoluto Genovese. Sauce comes through the tomato mill practically finished consistency and takes very little cooking down. I do make a tomato pesto using sun dried tomatoes but have not made sauce using partially dehydrated tomatoes. The varieties i use are also great for salsa. I HATE runny salsa!

I once knew a woman who canned many, many jars of tomatoes and tomato sauces of all kinds. She always used Paste Tomatoes, then she would cut them up and put them in a collandar to drain over night. She said that the 'water' that drained away wasn't needed and was bitter. Her sauces were always of the nicest consistency and very tasty.