The Klein Quartic meson mass program of Papers CCX–CCXII identifies two distinct mechanism classes for hadron mass generation in the One-Octonion Brane-Bulk Framework: surface mesons (π, K, η, η′), whose geodesics remain on or return to the brane surface, and single-H--crossing mesons (D, B), whose geodesics cross from the expressed H+ trinion sector to the non-expressed H- sector at the inradius scale rin = 0.5453. We introduce a third mechanism class — the dual-H- class — consisting of bound states of two simultaneous H- crossings. We derive its pseudoscalar/vector mass ratio from three framework inputs: (i) the Fano-chirality eigenvalue χq carried by each individual H- crossing, (ii) the genesis-tilt phase rotation exp(iχqθG2) (Paper CXXX), and (iii) the G2-locked spin-chirality correspondence (Papers CXXX, CCVIII, CXXXVIII). The Mode S (singlet) and Mode V (vector) decomposition follows: spin-singlet states map onto anti-aligned chirality with total phase 1; spin-triplet states map onto aligned chirality with M-averaged phase (1 + 2cos(2θG2))/3. The mass projection via the G2-singlet boundary condition at the H+/H- interface yields the central Theorem 6.1: mscalar/mvector = cos(2θG2) = 2389/2413 for any dual-H- pseudoscalar-vector pair at 1S, equivalently Δm/mscalar = 24/2389 ≈ 24/74. The unique QCD realization is the b̄c system; doubly-heavy tetraquark candidates Tcc, Tbc, Tbb provide forward tests. The Bc +–Bc *+ application to ATLAS arXiv:2605.16228 is presented in companion paper CCXLII. Part of the One-Octonion Brane-Bulk Framework series. Anchor DOI: 10.5281/zenodo.19120873. Community: one-octonion-brane-bulk. Author: Bharathi Dasan Jagadeesan, M.D., University of Minnesota. ORCID: 0000-0002-1143-941X.
Bharathi Jagadeesan (Tue,) studied this question.