I would say you are good if you kept the weight the same on the fronts. usaly they get a little bit lighter and you just minimize the amount. I have not seen actual weights used to adjust them, the tried and true method is to measure how much the front of the truck rises when you hook up and try get it to within a inch of the starting hight again.
Idealy you want to be as level as possible so you can measure the hight at the fron and at the rear cut the difference in half and thats how much you have to raise, or lower, the hight of your hitch. being out front to back can chage the how your trailer tires hold up if it is extreem enough, a little bit of nose down isn't to bad but if it can be corected I would readjust the hitch hight.
