Dark Souls 2

I managed to farm the one that drops off of casters in the Shrine before crypt. It is hands down the best sorcery catalyst in the game, especially if you are human while using it. Hexes will work better with the staff with the little atom on the end (forget the name) and the blue staff from the hidden wall in crypt is fairly solid, too, if you are too lazy to farm the Shrine one.

On your other question, I am working up my Int to do the top sorceries, but the sad fact is that the faith with hexes route is better. The poison cloud thing just completely trivializes the game in a lot of ways, PVE. And the dark vortex spell damn near one shots any trash out there (and a lot of players too) on top of being fast casting. Dark Orbs will out DPS any sorcery spell over the long haul and the sun bolt faith spell (55 Faith to use) out bursts anything short of fully tooled soul geyser. Plus, once you unlock the dark covenant, you get a hex that basically silences people for an extended period, access to a shield that can parry sorcery spells, and a hex that just plain absorbs enemy spells. My routine when dealing with invaders has typically been to get close, vortex, then sun bolt them while they are trying to stand back up if they are still alive. I had a pretty high success rate and I am shitty at PvP. Now that I have the final boss catalyst, they basically have to hope they can one shot me before vortex hits them to win or that they have Geyser. And if they do, I don't really care much because I have two life rings on rotation and paying 3k souls for the annoyance is a small setback.

So basically, if your entire PvP strategy is based on an ambush alpha strike (which is basically Geyser in a nutshell), then you won't like hexes at all. In any PvE situation or in prolonged fights, hexes are much better. Specifically, Dark Orb, the Vortex spell, the poison cloud, and the silence spell are the key ones to have. Of those, only the silence one is PvP centric. Most of the time I am running around in farm mode, I tend to have a bunch of soul lightning, silence, and vortex slotted (witch hat, attune 30) which is pretty much all I generally need for any situation in the game. I don't even have much in the way of casting speed boost, but I consider 150 casting speed the minimum acceptable level to be at for this setup. If you are just looking to farm people in PvP and nothing else, then your current build is likely the way to go, since getting the drop on people and alphastriking them is the best way to get easy kills in this series. You are basically playing this games version of the lag roll backstabber from DS1, which is the quickest path to racking up the tokens. Other builds, while stronger, require more work an execution in a fight, which will slow down your farm.

Correction, I am not using the Witch Tree Branch for my catalyst, but the white crystal ones that the casters in the shrine drop. Its effect is that it does more damage the more human you are. It can also be smithed up with standard titanite, which is awesome. In testing comparing it to the basic Sorc Staff +10, it did roughly 25% more damage when I was completely human with the various soul bolts. The hex dark shot thing it was marginally better (and marginally worse than the atom on the end staff thing), but the staff based hexes are kind of less useful late in the game anyhow. The only gear you ever really slot when hexing is the duration extender (or the Dark Cov ring for more damage) for boosting how long poison cloud sticks. I would imagine that Jin could likely one shot anyone with that particular staff in human form unless the happened to have a shield spell (or silence) up at the time.

Most of the best hex spells work off of the chime, anyhow, and the Chime of Want is vastly superior to anything I have found on that front. My AE vortexes hit most things twice for around 700-900 damage (plus knock down), which is better than anything (other than poison cloud) you are going to find on the staff side of hexes. All of the other point blank AE hexes are kind of junk, but Vortex is the real deal.

Vortex requires them to close. And a 1k hitting soul geyser from an invader is nearly impossible for someone to defend against with a typical PVE setups and (as you already pointed out) most PvP ones too. Not faulting you for it, since the game has PVP as a dedicated element, just saying that coming in and one shotting people from a mile away with a 1k+ soul geyser is not exacly taxing your skills. The guys who come in with fast weapons and play the block break mechanic game get a lot more respect out of me, because it takes some knowledge and effort to work that build in PvP.

My PBAE bullshit is just because I want to cope with PVP without hampering my PvE experience if I can. It also requires some timing and is only good for defending against invasion. Its not like you can run at people and PBAE cast in this game (and I literally never invade or invite PvP). If you are on a token farm, then by all means take the shortest route to victory because the bulk of the player base is going to do the same. If you are into dick measuring style PvP where the challenge means more than the raw wins, you might want to adopt a strategy that takes more than five seconds to execute.

Dragon is just about keeping close and not fucking up. If you stick close he almost never flies up. More DPS just shortens the fight. To survive his hits, you need stupid amounts of poise and defense. Most builds on the first run through (where you have a the best shot at winning) are not going to have the stats to eat a hit from the guy. Keeping to one side and patiently poking away is the trick to him. The minute you get greedy, you are dead. Elementally, he seems weak to Dark, but honestly any non fire weapon that you have the moveset down on is sufficient to the task. I would not recommend working that spawn until you extinct the shit on the run up to him, though, as you can lose your rhythm on that fight by having to do that freakishly long trash clear.

And weapon choice is pretty open in this game if you don't care about PvP. I beat it with a +10 Raw BK Halberd and a +10 Heide Spear as my reserve weapon.