The best "trick" I know of for getting a proper nock fit was passed on to me by Rod Jenkins. Just wrap dental floss at the nock point to get the fit you want, then add a drop of super glue to the floss.
Very large servings on very small diameter strings are apt to slip. Adding strands underneath makes for a lumpy serving. The floss is quick, easy, cheap, neat, and durable.
I don't use UC string material, but I can say that there are no "magic formulas"--you'll have to do some tinkering to find out what works best for you.
Chad