... Which helmet though? Again, specifically building around whatever weapon you plan to use makes worlds of difference. If you have the Kelvin Catalyst as Melee, you want the melee setup. If it's the Rogue variant, you want a Rogue setup. I have yet to dabble in Rogue damage, especially after all the changes and add ons, but I am pretty sure it has the opportunity to be pretty broken. And again, if you just get the consumable that gives your attacks Ichor, you won't need to worry about swapping to Golden Shower ever. It's pointless to start using a magick weapon when you have no magick increases. Summons are typically the only exception, as they are a "you summon it, they auto attack for you" so you don't have to actually worry about it. I would recommend also reforging it to Ruthless for the extra damage they will deal.While I haven't beaten the twins yet (current target), I did get extremely close several times, and all of those times seem to be at about midnight. So I'd say I more or less melt them in terms of damage.
SP in comparison, when he's just a head, it's like his defense didn't drop whatsoever. He takes about as much damage as when a twin is in phase 2 but the other is still in phase 1 (the phase 2 twin has super armor).
If you want to replicate my loadout and try it out for yourself, here it is (I don't really metagame so don't expect anything amazing):
Weapons : Godly Kelvin Catalyst + Golden Shower + Ancient Ice Chunks (4 with bewitching table) (i do know summoning items do less damage if the item isn't being held, but it's still extra damage)
Armor: Daedalus set with helmet
Accessories : Armored Counter Scarf, Guarding Siren's Heart, Armored Frostspark Boots, Hasty Frozen Wings (could probably reforge into something more useful but the cost for reforging wings is just terrible), Bloody Worm Scarf (forgot to reforge), Precise Charm of Myths (planning to upgrade this accessory into deific amulet so reforging is sort of redundant)
Edit: I want to clarify that I am not specializing in any kind of class at all, whenever I find a weapon that I deem is better than my old one I swap to it, whether it be ranged, rogue, mage, etc. then I proceed to use armor fit for that class instead.
I've also been collecting accessories, even if they don't fit my current class, for this. For instance, I have never stumbled upon a rogue weapon I want to use yet I still have made a mirage mirror.
(I run full summoner, sure, but I also still use a gun every so often... Still trying to find a good summon weapons so I can dedicate all damage ups specifically to summon damage, but until then I will still use the Lightning Hawk and Grenade Launcher from Calamity just because they have good damage without the need for the ranged armor bonus or accessories etc.)
Things like your mount can also be a big impact, because again you would typically be better off reforging for damage increases instead of trying to face tank through things. Especially if you aren't running a melee tank setup. So your best bet is to learn how to dodge, which is so much easier if you have a good mount. If you have done the Brimstone Elemental, you can get a flying mount off her. It's honestly my preferred mount for a lot of things because it flies, it's fast, and it isn't huge so I can use it while building etc.
Apologies to anyone else going through this forum thread and seeing our giant block text, I have left it in here in case anyone else has input that may be more helpful than my own