It's only after I accept the final story mission in Xenoblade Chronicles X and save over it that I learn where to obtain the Skell superweapon that's supposed to make the final bosses a cakewalk, and it's in an Affinity Mission. Guess I'll just have to tough it out with the Gravity Buster (the one that gives the Art Breaker Crush) as my best Skell weapon. Or buy another Level 50 Skell.