Climb Firefly for ten bolts. Head left toward the red-painted hanger. Find the good holds that lead to a position below the roof.
Search out unlikely holds and craft a plan of attack for the roof (but don't dawdle – the position below the roof is positive but a bit strenuous).
Once your feet are over the roof it's big holds to a final, not-too-difficult-but-never-the-less-exhilarating mantel-esqe move onto a big ledge and the chains.
If you use longer draws on the bolts of Firefly, and continue to do so up until the roof the rope drag will be minimal.
See Firefly. Heads left after the tenth bolt.
15 bolts (first 10 shared with Firefly), ring anchors over a ledge. Watch the ends of your rope on a 60 meter as this one will be close!