Notes from author
You've got a lot of options working with 16 Strength, 14 Dexterity, and 16 Intelligence. You've got a TON of weapons and shields available (far too many to list here) as well as a wide variety of sorceries. This build tries to capitalize on those strengths as much as possible.
Dark Bead and Dark Orb are available at 16 Int, and do a ton of damage with the Oolacile Ivory Catalyst. With the Crown of Dusk, the Bellowing Dragoncrest Ring, and Power Within, they're extremely powerful at this SL, often yielding one-hit-kills on other players.
16 Int also lets you apply a weapon buff, Great Magic Weapon, onto your right hand weapon. This'll give you an additional 198 magic damage. In many cases, though, you're better off using a fire or lightning elemental attribute on your primary weapon, hence why GMW was omitted from the actual build.
Havel's Gauntlets and the Hollow Soldier Wastecloth aren't the most protective or fashionable of gear, but they'll give you 35 poise, enough to deal with a single hit from nearly any light or medium weapon in the game.
But, the armor you wear is highly determinate on what weapons you plan on using. The highest weight weapons you can use with the stats presented here exceed 10, so the armor you use will have to vary depending on your weapon and shield of choice. Havel's Gauntlets and the Hollow Soldier Wastecloth are just a recommendation, and happen to work very well on this build, and it would be a good idea to instead pick weapons that you can use alongside this armor selection.
tl;dr: 35 poise, very strong Dark Bead castings, decent survivability, USE ELEMENTAL (Fire, Chaos, or Lightning) WEAPONS. This build performs VERY favorably against other people in this SL range, especially in a SL 50 arena setting.