You shouldn't need much... Bru'n Water says something like 4.5 grams gypsum to mash, 1.5 grams epsom salt to mash, and then depending on sparge volume, 3ish grams gypsum to kettle, 1ish gram epsom salt to kettle.
That will bring mash ph to 5.3 and water profile to:
47ca 7mg 8na 137so4 4cl 16hco3
That is what I would do anyways... some others might want to bump up bicarb more and try to make the water more "English" but I like a crisper profile.