Help with ninja / vivisectionist build for PFS play

[Gibo Auja]

So I want to make a TWF in PFS ninja2/vivasectionist10
Heres the first couple of lvls
any advice for further feats?
Human
Ninja

str 10
dex 19
con 12
int 14
wis 10
cha 10
----levels 1-2 -----
two weapon fighting lvl1
weapon fineese lvl1(human bonus)
pirahna strike ninja trick
--------------------
going to get agile weapons eventually

this sets me back a bit with BAB, but I get wakizashi feat
and ninja trick.

So what do you guys think, worth going this way or should I just
go straight Vivasectionist. I lose wakizashi or any good crit based
weapon.
Also what do you guys think of the ability scores I choose
should i raise or lower int for Viva, do they really need high int?
Should I do anything with charisma, for the ninja ki an extra attack
is pretty useful.

[StreamOfTheSky]

Sneak attacks don't multiply on a crit so I don't see why you care about the high crit range weapons. As for piranha strike... ok for when you can't SA, I guess, but the attack penalty isn't worth it when you can, too much damage is on the line.

I'd suggest not doing ninja at all and dumping the hell out of charisma. But it's up to you. If I were to dip at all as a Viv, it'd probably be either Beastmaster Ranger for class skills or Waves mystery Oracle for Water Sight + Obscuring Mist combo.