heroic aat squads to use

3cheers4tyranny gave good recommendations, although you can't use St Han in both P3 and P4 for heroic raids. There are other squad compositions that also do well. I consider anything over 2% in a phase as gravy. Over 4% is just fantastic. I have some guild mates that can hit 7-10% in P1, which is just stellar. Here is what I use:

Yoda (L), Qui-Gon, Luminara, Ahsoka, Ima-Gun Di. Load them with tenacity crosses and secondaries. Best hit was just over 5%.

HK-47 (L), 88, 86, JE, Nebit. No surprises here. My best was 5.1%, but I've seen twice that.

Teebo (L), Palpenstein, TFP, St Han, RG. Best was 7.2%.

Wedge (L), Biggs, Lando, Leia, Ackbar. No surprises here either.

The teams work and allow me to put in my quota without requiring farming all the newer, better heroes. I can still use Lumi! Yeah, other squads have better potential, but these get the job done and give me efficient use of my existing roster.
5% Yoda lead http://i.imgur.com/dEwTKJl.jpg
7.2% Tiebotine http://i.imgur.com/WwTHdq5.jpg