I use a pound of spag for a 9x13  cooked
Usually left over sauce and meatballs
but I have cooked hamburg and added a jar of sauce
 
Sauce on bottom, half spag,ricotta,hand full of schredded motz and cheddar cheese,sauce
Spag motz,cheddar ,sauce.     Then I use a can of mushroom soup and mix it with half can milk
Pour over the top and sprinkle with parm,  bake until bubbly around the edges.  350