I think I read that you can use the TF100 FC test for bromine as well and the conversion ratio is 2.3 (or 2.25 or 2.5) x FC = bromine ppm (but I can't find the posts now). So I should multiply the number of drops by 0.5x2.3 to get the bromine level? Is this correct?

If so then I should plan to maintain bromine at 4-6 ppm level using this test if using the 3-step process?

Yes you can, and the conversion factor is 2.25. FC x 2.25 = bromine ppm in bromine sanitized water.