What's important here is getting the most bang for your buck. 40 is absolute max you'd need. I have 35 vit now, and I'm killing everything in PvP even without the Mask of The Mother. I'd say fuck washing pole. Go 40 DEX, 40 INT. There's no point in taking INT higher, lest you want Crystal Spear, but that's very poor for PvPing, and you can get both Crystal Magic Weapon and Crystal Homing Soulmass.
Above 40 int, catalysts no longer skyrocket in terms of MagAdjust (check this out:
http://sites.google.com/site/darksoulstats/dark-souls-calculators/catalyst-talisman) - the same with Dex for a +15 Uchigatana (check:
http://sites.google.com/site/darksoulstats/dark-souls-calculators/normal) so 40 DEX, 40 INT is getting the most bang for your buck.
Even with 16, you're only 2 over the ideal 14, so you're still on course for the (in my view) best build in the game. Tin Crystallization Catalyst + CMW + +15 Uchi - you'll kill everyone you face. Again, I'm at 35 VIT, 40 END DEX INT, best build ever.