You need a swing weight scale to determine that. In general lighter shafts have heavier head weights and vice versa to make the swing weight feel the same. Going to graphite at the same length will lowers swing weight but you may like it. An example is when players try KBS shafts. They usually come in 2 or more swing weight points less. I have found that several players like the feel. 

Bottom line. Put one together. Don't use a tip weight as they often add length in graphite. Buy a roll of lead tape and experiment with the feel. When you get one club where you like it, get it measured for swing weight and make the rest the same. There is more art to this than science. If YOU like the feel and performance that's all that matters.