yes, these are the perfect orders for narrow diamond. hey also if you want to dominate the middle more, you could sub your DMC for an MC, and use a 4-3n-1-2. this will mean you will dominate the middle of the pitch.
4-3n-1-2 should be exact same orders and arrow placements as the 4-1-2-1-2 nd. but start with the 4-1-2-1-2 nd and see if that works better for you.