can you feel my heart?
If you're gonna use Dragonite, you need to use Multiscale as it's by far the best ability to use on it (plus you have Icicle Crash on your Mamo so I'm assuming Gen V anyway). If you don't have access to Multiscale (which you probably could get - plenty of people should have it around forums and such) then Dragonite is otherwise an inferior Salamence. :(
I think if you want to have an annoying Serperior set you might want to ditch the TrickScarf part and rather go with a SubCoil set with Glare. You boost Serperior's defenses while paralyzing everything and phazing them with Dragon Tail, spreading paralysis really easily which is always helpful for any team. You could try out the set:
Serperior @ Leftovers
Jolly Nature (+Spe, -SpA)
EVs: 252 HP / 252 Spe / 4 SpD
- Dragon Tail
If you have any trouble with other movesets or want to test something new out, don't be afraid to post!