IG88 I think. Most of 47's benefit is in the leader ability, 88 could use both the dps and health more (47 can revive anyway so health pool is less of a priority).
Edit: I assumed from the OP that he was already using both 47 and 88 and just needed to star them one at a time. But Harmson is right that 47 is probably a bigger priority to get on your team (although I'd probably go Poggle L, Poe, GS, 86, 88 before HK L, Poggle, 88, non-droid, non-droid).