I didn't substitute anything or add anything else. Came out quite nice, but two things I'd recommend:
1. Use less broth, my rice came out just a little overdone as is so by the time the shrimps were done they were very overdone and almost completely mush.
2. Cook the shrimp separately. I had to flip through the rice multiple times to make sure everything cooked all the way through because not all the pieces had on their own. Cooking separately will not only be easier to keep track of cooking, but will also help keep some seasoning stuck to the shrimps.
As someone used to spice, it came out quite mild for me but still on the slightly salty side. So careful of that
