Need help with a Pyro PVP build

So for my main weapon I'm undecided between a chaos uchi/wash-pole, and quelaag's furysword. With dex at 40, they are the same (pretty much), but with the minimum dex requirements the chaos uchi is better.

My question is, considering that dex makes you cast faster, should I put my dex at 40 and use quelaag's and be a higher SL?
or should i keep low dex and use the chaos, with slower casting and lower SL/invest points in VIT/END?

I'd like to stay around 70-80 to invade people.
Also, if you'd like to suggest a more appropriate SL range, please do.

ALL commentaries are appreciated

http://tinyurl.com/cpezovq

Here's a SL 80 pyro stats. Just tweak Att, Vit and End to your liking.

SL 99 is a good level. You can reach the down to 80 or up 120 if you invade as a dark moon.

thanks, so what weapon would you suggest for this?

Dex scaling weapons. I never go elemental. Balder side sword is what I use. Great scythe, Ricard's rapier, whips, katanas. Just try them all and see what you like.