I've been working on squeezing as much DPS as possible from the general Sabdancer spec, and I've come up with a Puncture-less spec that has been giving me slightly better results on both single and multi-targets. I have humbly interjected my own name into the spec:
Dundancer - 26 Sab / 20 Sin / 20 BD
The only real change in this from the standard Sabdancer, is that you don't get puncture, and instead get another point in Ambidextrous for 3% more dex. The real refinement is in the rotation:
Spike x4 > Keen > Deadly > Precision > Spike > Detonate
Shrapnel x5 > Detonate
What this does is allow you to use the "extra" Deadly Dance charge in the standard Sabdancer rotation to power a Precision Strike. This offers superior single target damage compared with standard Sabdancer, both by utilizing this strike and by no longer needing to take Puncture, to get more dex.
For AOE situations, such as Zilas and Matron, you can still just drop Precision from your rotation to maximize AOE damage.
This isn't going to move you from #7 to #1 on the damage meters, but it should help you eek out an additional few percentage points of damage. With HK's tight tuning, this can mean the difference between victory and a 1% wipe. Hope it helps!