Measuring by weight and measuring by volume aren't quite the same. Going by a line mark you made isn't *overly* accurate IMO. Personally, I wouldn't go with this method. Now if you had 2 lbs of wax that were all scented the same and you just wanted it in 2 different colors, I wouldn't worry too much about that. It's really the FO that scares me about this more then the dyes. For example, when I make Pearberry, I do a dual color, berry bottom and pear top. All the wax gets scented then I pour out 2 pots and dye each one individually.