There is a shaft performance guide of shafts Titleist has tested. If you hover over clubs, there is a custom/option button to get to shaft options. I'll guess you'll get these rebuilt at a local shop. They can look at the suggestions (graphite, under 80 g, mid-high launch/spin, etc) and recommend something. They'll also need to attempt to adjust the weight to get to that swing weight where you want it. Titleist doesn't offer club rebuild services.

You may also want to check the street price for the shafts. They could vary from $30 raw cost to "the sky's the limit" per shaft. Plus the rebuild service and grip install.