Coordinate Subcubes of Weaver Partitions at the MSS Bound

Let v_1,...,v_m in C^d be a Parseval frame with squared norms at most alpha. At the historical Marcus-Spielman-Srivastava discrepancy bound sqrt(8 alpha)+2 alpha, we exhibit an entire coordinate subcube of good signings. If 0<alpha<(3-2 sqrt(2))/2 and r=ceil((3+2 sqrt(2))/alpha), at least ceil(m/r) signs can be chosen arbitrarily while every other sign remains fixed. Consequently there are at least 2^ceil(m/r) unordered good partitions. The argument removes an operator-small part given by the MSS partition theorem and applies the sharper Bownik-Casazza-Marcus-Speegle bound to its normalized complement. Prior work, including Akbas and Sra, already provides counting estimates at universal-constant discrepancy scales; this note concerns the coordinate-subcube conclusion at the explicit MSS bound. The result is not a sharp enumeration or closure of the entire AIM quantitative agenda. This is an unrefereed, self-audited preprint with AI assistance; independent review, formal verification and absolute priority are not claimed.