When you buy a two pack of butts, the money muscle is usually positioned away from each other in the packaging. If you are looking at a single butt, there are three sides that are cut, and one side with a rounded edge. On that edge are chevron shaped striations. That edge is the money muscle. The money muscle usually gets done before the rest of the butt. If you are doing pulled pork, you can just leave it attached until the other portions are done and then pull it all at the same time.
If you are trying to do slices with the money muscle, remove it from the butt when it hits 194F, and put the remainder back on until it gets done. Then you can slice it into pieces that are about an inch thick when you are ready to serve.
Is this question geared toward backyard cooking or are you doing competition?