Advice on tomato sauce making

I am planning to make it with both fresh tomatoes i got from a family member and canned diced tomatoes i have lying around. The recipe i'm using calls for the tomatoes to be diced in a food processor. My question is whether i should worry about the tomato juice in the canned diced tomatoes messing up the sauce

Am i worrying to much, or should i strain/filter out the tomato juice before putting them in?

Like in marinara/ pasta sauce or straight tomato sauce?

marinara sauce then no the liquid will cook out and it will help stew the sauce. i would strain the juice and save it until the stewing process.

This. I plan to use the sauce to make lasagna

For lasagna then you just want the tomatoes since soupy sauce isn't great on lasagna. Cook the fresh until all the water is out and strain it with the canned. Then simmer the tomatoes with oil, and other herbs and garlic. A little wine wine will bring out the alcohol soluble flavors. If the noodles are boiled kind then it perfect because the excess water remelts with the sauce.

Thanks for the tip. For the lasagna i was going to use pre-boiled noodles(I have a bunch of them because its impossible to buy a small amount of them from the supermarket). Should put a little water in to remelt the sauce when making it?

I don't plan on making the lasgana right after making the sauce btw, in case that affects your answer

If that the case did you have to see what the sauce will look like cool.. their should be enough moisture in the sauce, if it too thick then a little water to loosen it up.

Also, to cook the water out the fresh tomatoes, does blanching them for a minute accomplish that(The tomato recipe i'm using has that as the first step) or is there something else i should do?

Blanching makes the tomato's skin peel off easier. Which is good because the skins do have compounds that make stuff biter and stringy. It's really a question on what your taste is. Personally i like thick meaty sauces that hold to the dish, but a consistency of good ol' Spaghetti sauce is just fine.

Concasse the tomatoes though, meaning cut out the the top core and score the bottom put them in boiling water for about 30 seconds and then put it into an ice bath. That should make peeling the skin really easy, and then you wanna deseed it, and it's easier to deseed the tomato under water.

If i don't deseed it will there be seeds in the sauce, or will they kind of cook away?

They will be in the sauce, and science hasn't found a way to just cook them away, without burning the sauce.

Okay then, so what is the easiest way to deseed tomatoes?

After you're done peeling the skin cut the tomato in half and just scoop out the seeds, it's easier to do this with the tomato submerged in water.

I am actually almost done with the sauce(Another 2 hours of simmering and it should be done). I tried to use everything i saw about tomato sauce making on the internet, so hopefully it will end up at least being decent

as long as you add oregano then you'll be fine.