Hi.
Depends on your assigned profile.
First Solution: assign any profile you want (doesn’t matter), change the values of haze removel tool as you like, save profile file (.pp3) to your “profiles” directory (default: “C:/Users/Username/AppData/Local/RawTherapee/profiles” in Windows10), load or assign this profile to other photos as you want…
Second solution: open such a profile (.pp3) file in a text editor, search for “haze removal”, change values, save and close .pp3 file.
Third solution: http://rawpedia.rawtherapee.com/Creating_processing_profiles_for_general_use
Regards
Just in case you hadn’t realised, in RawTherapee or ART, you can save a profile (it might be the default profile) with the values of any tool changed but without the tool being activated. That way, the tool not activated by default, but when you click on it, it will apply your favourite values…
Hope this helps…