Learn the basics of sauces from a French cooking book/course.

Make a blonde roux, for 4 pounds of cheese, add 1.5 cups of milk and 2 cups of half and half. Add in the shredded cheese saving about a pound to a pound and a half for layering. Add 4 tsp of sodium citrate. Voila you have a cheese sauce that won’t break on you that pours into the pasta easily.