She runs great with JTR, BB8, Scav Rey, and RT in HSTR. If you're still doing Tiers 1 - 6 I'd recommend using the traditional JTR, BB8, R2, Scav Rey, and RT (if they're G10 or 11). You do more damage with that setup. Even in Heroic, that set of 5 has a higher ceiling, but Visas is WAAAYYYY more predictable and makes managing the phase so much easier.
If you're running the lower tiers without JTR, Visas is still the best complement to any team. Get her zeta'd and you'll never have to worry about toons not making it to enrage ever again. She also has the upside of almost never being needed in platoons and works great with any team in LSTB.
On Heroic, keep her speed low and trigger the green shield even when annihilate is at a 2 or 3 cool down. She counters 100% so being triple attacked will ensure she makes it to the annihilate before her shield wears off.
Personally, I'm regularly doing between 8 - 9.5% on P1 HSTR without any restarts.