If you can't get a platoon lance (huge DMG rating for its level) use Cruel spear until 23 when you can get San d'Orean/Kingdom spear (+attack)
The Fuscina isn't going to hit noticeably harder than the Cruel spear and the evasion down done to the mob is better than the minuscule lightning damage of Fuscina (which only happens like 5 out of every 100 swings anyway).
There's a reason Platoon Lance is more expensive. For a Dragoon, once you hit 20 you can stick with lances apart from a detour at 30 for a Royal Squire's Halberd.
Please, please, please, no more Dragoons with Fuscina >< You make me /cry.
