Sulfate or sulfites don’t boil off. If you insist on treating the chloroamines, which I doubt the need to do so because they are nonreactive anyway (unless in sufficient quantity to smell them, then I would trade off that for the added sulfates), please check out the link from Wisconsin dnr for water treatment for amount to add calculations. You’ll need to know how much is present though. Chlorine itself it much easier to remove either through activated carbon filtering or just letting it sit. That seems very practical to me as a basic protection with little more required than some forethought, ie fill up your HLT the night prior and let sit.
Sulfites tend to work more on bacteria in the presence of oxygen. It forms hydrogen peroxide and selectively kills microorganisms without peroxidase activity.
So that’s why it’s so important in winemaking. Take out the bacteria that spoil batches without hurting yeast too much.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC168295/
I personally don’t like the idea of adding sulfates/sulfites to beer. The boil takes care of the microbes before fermentation and the chlorine can be treated in other ways without the addition of sulphur, something usually not pleasant to smell, taste, and it can cause negative reactions (medical) to some individuals.
