This paper continues earlier work on the quantum evaporation of black holes. This work has been concerned with the calculation and understanding of quantum amplitudes for final data perturbed slightly away from spherical symmetry on a space-like hypersurface Σ F at a late Lorentzian time T . For initial data, we take, for simplicity, sphericallysymmetric asymptotically-flat data for Einstein gravity with a massless scalar field on an initial surface Σ I at time t = 0 . Together, such boundary data give a quantum analogue of classical Einstein/scalar gravitational collapse to a black hole, perhaps starting from a diffuse, early-time configuration. Quantum amplitudes are calculated following Feynman's approach, by first rotating: T → |T | exp(−iθ) into the complex, where 0 < θ ≤ π/2 , then solving the corresponding complex classical boundary-value problem, which is expected to be well-posed provided θ > 0 , and computing its classical Lorentzian action S class and corresponding semi-classical quantum amplitude, proportional to exp(iS class ). For a locally-supersymmetric Lagrangian, describing supergravity coupled to supermatter, any loop corrections will be negligible, provided that the frequencies involved in the boundary data are well below the Planck scale. Finally, the Lorentzian amplitude is recovered by taking the limit θ → 0 + of the semi-classical amplitude. In the black-hole case, by studying the linearised spin-0 or spin-2 classical solutions in the above (slightly complexified) case, for the corresponding classical boundary-value problem with the given perturbative data on Σ F , one can compute an effective energy-momentum tensor < T µν > EF F , which has been averaged over several wavelengths of the radiation, and which describes the averaged extra energy-momentum contribution in the Einstein field equations, due to the perturbations. In general, this averaged extra contribution will be spherically symmetric, being of the form of a null fluid, describing the radiation (of quantum origin) streaming radially outwards. The corresponding space-time metric, in this region containing radially outgoing radiation, is of the Vaidya form. This, in turn, justifies the treatment of the adiabatic radial mode equations, for spins s = 0 and s = 2 , which is used elsewhere in this work.