  We calibrate a neutrino transport approximation, called Advanced Spectral
Leakage (ASL), with the purpose of modeling neutrino-driven winds in neutron
star mergers. Based on a number of snapshots we gauge the ASL parameters by
comparing against both the two-moment (M1) scheme implemented in the FLASH code
and the Monte Carlo neutrino code Sedonu. The ASL scheme contains three
parameters, the least robust of which results to be a blocking parameter for
electron neutrinos and anti-neutrinos. The parameter steering the angular
distribution of neutrino heating is re-calibrated compared to the earlier work.
We also present a new, fast and mesh-free algorithm for calculating spectral
optical depths, which, when using Smoothed Particle Hydrodynamics (SPH), makes
the neutrino transport completely particle-based. We estimate a speed-up of a
factor of 100 in the optical depth calculation when comparing to a grid-based
approach. In the suggested calibration we recover luminosities and mean
energies within 25%. A comparison of the rates of change of internal energy and
electron fraction in the neutrino-driven wind suggests comparable accuracies of
ASL and M1, but a higher computational efficiency of the ASL scheme. We
estimate that the ratio between the CPU hours spent on the ASL neutrino scheme
and those spent on the hydrodynamics is 0.8 per timestep when considering the
SPH code MAGMA2 as source code for the Lagrangian hydrodynamics, to be compared
with a factor of 10 from the M1 in FLASH.
