Just a slghtly different view point from the peanut gallery. Pat Johnston showed me this technique, hes great at making reliable, repeatable techniques. For tip weight, after the plane is completly finished, turn it upside down on the rudder tip and the front of the fuselage so it rocks ,(might actually sit on canopy and padding is a good idea) put your scale under the outboard wintg tip, and add lead till you get the tip to physically weigh 1 oz, or on some larger planes 1.25. Of course there are a lot of variables, wing assymetry among them.
while I am on the subject, if you want yoru plane to land on asphalt and have conficence it will, block your complete plane up so its sitting level with the scale under the tailwheel. If the weight on the tailwheel (WITH THE PLANE SITTING IN LEVEL FLIGHT ATTITUDE) IS between 10 and 15 percent of the total flying weight you are golden. It has worked every time for me,, just another idea,,