There is little luck involved about getting the Dark Catastrophe with implementation of pity system (another thing to write about).
Dark Catastrophe probably will be released in a rate up banner, so one just needs to have saved 90k MJ by October...
So, with Assault issues solved by having that Eidolon, a Vigoras Staff grid for dark could be:
4 Dragon Cane on Huros (Vigoras cap achieved with help of Dark Cata)
1 Phantom Calamity Staff
2 Jealous Hammer Rebel Punisher (90% Burst Damage Cap Up achieved with help of Dark Cata, just short of the 100% cap. As it has the ill-needed Assault, having a third hammer is not bad)
1 Soul Weapon (if a Staff, phantom grid enabled, otherwise, another staff is required)
1 or 2 flex slots (Ideally would go with 1 or 2 Nefertem Staves, which bring Ascension and Assault)