Tried before 2 viet sisters working at the same shop. Elder sis first, then when one day she busy, recommended her younger sis. Subsequently I sometimes alternate between the two. Each got their own strengths.
No tarma because it was a "clean" shop
No awkwardness, and it only got awkward later on when they graduated to offering hj, then ask if I received from the other sister.
Now they each work on opposite side of SG, different shops, and I only stuck with one that's nearby!