lol nice choice. I love the dragon destroyer. It's pretty expensive though, i got the atlas crusher, i'm gonna branch off and get the dragon destroyer //.^ I'm still farmin' Lao for it. But don't forget to combine your armor/power charms with lao shan claws to get power/armor talons you can stack with your charms. They REALLY help with hammers and such.
But that's a much better weapon than the sword from rust stone, trust me. Why do you think it's so expensive?
Btw, a good GS w/dragon is Obelion, it's from the bone path past golem blade. It requires Azure Rathalos materials but it's really good :p Btw the Plesioth GS is a great water weapon for when you need water, it's not high rank but the upgrade is, so when you get to HR2-3 wit ur bro you need to farm plessi for a really bad-ass weapon :p