  We discuss preliminaries of a calculation of the form factors for the
semileptonic decays B -> pi lv, B_s -> K lv, and B -> K ll. We simulate with
NRQCD heavy and HISQ light valence quarks on the MILC 2+1 dynamical asqtad
configurations. The form factors are calculated over a range of momentum
transfer to allow determination of their shape and the extraction of |V_ub|.
Additionally, we are calculating ratios of these form factors to those for the
unphysical decay B_s -> eta_s. We are studying the possibility of combining
these precisely determined ratios with future calculations of B_s ->eta_s using
HISQ b-quarks to generate form factors with significantly reduced errors.
