Roast Beef

I would like to make some smoked roast beef in my WSM and then shave it for Deli style sandwiches. This may be a dumb question, but what is the best cut of meat to use in order to end up with Deli style roast beef? Thanks in advance

Top Sirloin Roast would work well.
They are 10 pounds and larger.
Smoke to 135* internal, let cool for best slicing that thin.
Jim