What should I buy?

Dou eclipse and lr hasbro launcher or dragoon f, winning valkrie lr hasbro launcher and ZA
Duo Eclipse's Layers are only good for collection because they're so lightweight, they'll burst against anything. Though all the other parts are good, though getting them through Duo Eclipse can be way too expensive, depends on whether or not you can get it for cheap
Maybe winning Valkyrie since the layer seems pretty great at attack but then it comes to 12.......
The launcher is only good depending on your collection so far. Only get it if you don't have a string launcher or Left launcher.
Duo Eclipse is bad, only good thing being the gimmick
Winning Valkyrie is good for attack, and it's new. 12 can cause damage, so if you have a frame put it on wV immediately
Dragoon F is bad straight out of the box, so you should wear down the variable. The layer has good teeth, which is good. Gravity is outclassed, so don't use it.
Zet Achilles is great with an attack type tip. I would recommend replacing Xt because it is unstable. 11 is decent, so you could replace it.

The best options are wV and the Hasbro string launcher.