I tend to use the yellow bitter with the ph brought down to 5.2-5.3. I like a drier finish and a touch lower ph in the beer.
There are plenty of differing ideas on water profiles for saisons. Some people like balanced profiles, others like to try to emulate profiles across Wallonia while others adopt the NE/Vermont water profile used in Hill Farmstead and other saisons in the area that are softer and more chloride-forward. The question is more what do you want from the water rather than what you need the water to do.