With Meat Sauce for 50 persons
Double this Recipe for 100 Persons

10 lbs spaghetti
6 lbs ground hamburger
2 lbs sweet or mild ground sausage
8 small onions
1 cup of the hamburger drippings
2 teaspoons pepper
5 (No. 10) cans chopped tomatoes (Each No. 10  can of tomatoes may weight  6 lb 8 oz to 7 lb. 5 oz and will yield 12-13 cups)
1 quart buttered bread crumbs
4 tablespoons salt

Cook spaghetti in boiling salted water until tender; drain. Brown the meat and minced onions. Mix the tomatoes, salt, pepper and the cup of oil drippings together then mix it into the spaghetti,  add and mix in the fried hamburger and onions. Spread out into baking pans. Cover with buttered bread crumbs. Bake at 300-F for 30 minutes.

If you want, you can also spice up the sauce by adding small amounts of some, or any,  of the following (Add to taste but taste often)
Fresh Parsley 
Can Mushrooms, drained 
Hot sauce
Sugar, white or brown
Diced green pepper
Dried leaf basil
Garlic powder 
Dried leaf oregano

Meatball Sauce
Sauce Ingredients
½ cup olive oil  
4 garlic clove, chopped fine  
3 large onion or 4 medium, chopped  
4 cans (28 oz each) diced tomatoes  
4 cans (16 oz each) tomato sauce  
4 cups water  
2 tablespoons dried basil  
1 teaspoon black pepper  
3 teaspoons salt  
4 teaspoons oregano  

Meatball Sauce Instructions
Add the onion and garlic in the olive oil, brown until transparent. Transfer it to a pot. Add the rest of the ingredients to pot and simmer for 30 minutes or longer, stirring often. Pour sauce over meatballs.

100+ Meatballs (about 2 oz. each)
18 lbs ground beef 
16 eggs 
3 tablespoon black pepper 
4 large onions, chopped very fine 
6 cloves garlic, minced 
6 cups Italian bread crumbs
3 cups grated Parmesan cheese
About 4 to 6 cups water, enough to make soft mixture, don't add all of the water at one time. Mixture should be moist but not so that the meatballs fall apart. 

Combine all. Wet hands and shape all into meatballs by hand about the size of a ping-pong ball, they will lose 1/3 their size after cooking.
Bake in oven 1 hour, remove pan and pour off oil, pour sauce over them and return to oven. Total baking time at 325-F (1-1/2 to 2 hours.)

Depending on the size and how many made - Add 2-3 meatballs and some sauce to each spaghetti serving. 

Research explained that pasta can be cooked ahead of time (day before), then cooled quickly in cold water, drained then toss lightly with cooking oil to keep it from sticking together, covered with plastic wrap or damp towels and stored in a refrigerator or walk-in cooler overnight- in big buckets. So, if you have the time or access to the kitchen make both the sauce and pasta and also the meatballs and meatball sauce ahead of time. 

Unless you have professional sized pots, it's easier to cook sauces in batches that would serve 25, just make two batches for 50 and 4 batches for 100. 

If you are cooking pasta at the time of serving, it is very difficult to work with. The water takes a VERY long time to boil, and you can only cook 2 batches of pasta before the water gets too starchy and requires changing  so.. the reheating is better. Next day the cooked spaghetti noodles mixed with the pre-made sauce can be mixed together and placed in the oven to reheat. The meatballs and meatball sauce will also have to be re-warmed if it was made the day before and of course refrigerated (which is a good suggestion if you only have one oven) so it could be heated in pots using the stove top.

Add a sprig of fresh parsley and a crab apple slice to the side of each plate of spaghetti.

While everything is being re-heated make a fresh salad of your choice.
Slice loaves of french bread to be served with pads of unsalted butter.
Fill salt and pepper shakers and open containers of Parmesan cheese to be placed on guests tables.