CDN-167 narrows theory debt D5. Taking the CDN-166 time-domain drag curve as the velocity-window shape W(v/v*), a scan over the Local Group finds that v* ∈ 98, 174 km/s simultaneously satisfies three requirements: W ≥ 0.8 at the MW–M31 approach (110 km/s, preserving the CDN-139 flyby signal), W ≥ 0.8 at Crater II (~100 km/s, preserving the rescue signature), and W ≤ 0.2 at the LMC/stream velocity (310 km/s). Within this interval the CDN-161 stream suppression shrinks from ×0.44 to ≈×0.9, re-entering the CDN-160 measured range — the upper screening window and the stream data can coexist if the window is real, and the 3D/hydro check sharpens from "is the suppression real?" to "is the window shape right?". The note pre-registers the DR4 velocity sort: satellite anomaly amplitudes A ∝ f(ρ)·W(v/v*), so anomalies sort by velocity at fixed radius — a fast outer satellite (v ≳ 250 km/s) showing the full anomaly kills the window, while anomalies confined to slow satellites at all radii kills pure density screening. This supersedes the flat population expectation of CDN-149/155 T4. Conditional on the toy window shape; R1–R3 are desiderata, not fits; v* remains underived — if no Lagrangian produces a scale in the interval, the window is falsifiable theory-side. Scan script, results JSON, and figure included. By Nicky Hacquier (Aporion Dynamics) — Project Aporion; follows CDN-166 (DOI 10.5281/zenodo.20634793).
Nicky Joseph Hubertus Catharina Hacquier (Thu,) studied this question.