I think calculating % by each day will make you too many dissapointments!
I have a goal of how many pips I want a month and when I was to go by days friday could have left me very down in the dumps with the abrupt drop in g/u g/j.
But overall I had a profittable week, so I think you're better off to look at your gains or losses over a longer term...A lot less stressfull. . imo