We develop an idealized framework for recovering coincidence-conditioned Compton-modulation levels from 511 keV photon pairs produced in electron–positron annihilation and described by a Bell state. Compton scattering followed by angular post-selection in the signal arm defines a coincidence-conditioned idler ensemble whose degree of polarization is determined by the selected signal-arm scattering angle. The ensemble is analyzed through the azimuthal modulation of the idler Compton-scattering distribution. Two prescribed signal-arm angles, α1 = 45° and α2 = 81.7°, give ideal narrow-signal-channel, full-polar-angle relative modulation depths of approximately 0.10962 and 0.23758, respectively, and thereby define a binary discrimination task. Time-tagged coincidence data are partitioned into successive acquisition intervals, and each interval is classified using an unbiased estimator of its idler modulation depth. For the prescribed pair α1 = 45° and α2 = 81.7°, a finite-statistics analysis gives a conservative event requirement of approximately 2 × 10^3 retained coincidences per interval for the two-sided 95% separation criterion used here. More generally, the required count increases rapidly as the two modulation levels approach one another. Finite angular acceptance, reconstruction resolution, and azimuthally uniform uncorrelated background are incorporated through a reconstructed modulation depth, while the corresponding acquisition-time scale depends additionally on the retained coincidence rate. The resulting framework provides an operational Bell-state baseline for coincidence-conditioned Compton-modulation recovery and for assessing detector-dependent departures from the ideal response.