  We introduce a comprehensive numerical framework to generically infer the
emergent macroscopic properties of uniaxial nematic and cholesteric phases from
that of their microscopic constituent mesogens. This approach, based on the
full numerical resolution of the Poniewierski-Stecki equations in the weak
chirality limit, may expediently handle a wide range of particle models through
the use of Monte-Carlo sampling for all virial-type integrals. Its predictions
in terms of equilibrium cholesteric structures are found to be in excellent
agreement with previous full-functional descriptions, thereby demonstrating the
quantitative validity of the perturbative treatment of chirality for pitch
lengths as short as a few dozen particle diameters. Furthermore, the use of the
full angle-dependent virial coefficients in the Onsager-Parsons-Lee formalism
increases its numerical efficiency by several orders of magnitude over that of
these previous methods. The comparison of our results with numerical
simulations however reveals some shortcomings of the Parsons-Lee approximation
for systems of strongly non-convex particles, notwithstanding the accurate
inclusion of their full effective molecular volume. Further potential
limitations of our theory in terms of phase symmetry assumptions are also
examined, and prospective directions for future improvements discussed.
