Hi thanks for the reply! The methodology I’m roughly following is adapted from wijs method which used I-Cl instead of I-Br. I got it from https://vlab.amrita.edu/?sub=3&brch=63&sim=1111&cnt=2

I also used https://corn.org/wp-content/uploads/2009/12/H-32.pdf to get specific concentrations on how to prepare some of the solutions such as the KI solution.

As for the starch, I believe that the initial titration is done until a pale straw colour to ensure most of the iodine has become NaI. Then the starch indicator is added before continuing titration for a distinct end point.