This recipe makes a large amount of apple butter. When I made it it filled about 7 (1/2 pint) jars.
I usually just mix this together by guessing measurements. You can usually tell if there is enough mustard if you mix it together and it doesn't immediately separate.
*If you want to make this sauce as a salad dressing, add a small amount of vinegar until it is the taste/consistency you would like.