I have treated white spot on my tanks twice in the last few months and ive had bristlenoses in them everytime, I used the blue circle whit spot cure and found it worked well. When the white spot was very minor it was gone after the first few days of treatment but I always redose on the 3rd day to ensure its well and truly gone..
Ive always used a full dose on my tanks and haven't ever lost a fish let alone a bristlenose, im unsure if thast whats recommended but its what ive always done and had no problems..
Good luck!