The Chosen Tensor, Priced: Einstein's 1915 Field Equation, Its Matched Coupling, and the 43 Arcseconds It Returns

Census pricing (row CC-100) of the field-equation step of Einstein's 'Die Feldgleichungen der Gravitation,' Sitzungsber. Preuss. Akad. Wiss. (1915) 844-847, against a fixed bench (what is postulated, what is derived, what the postulates return numerically, what they cannot reach). The step is two-layered: the Einstein tensor is CHOSEN under stated demands (covariance, second order, divergence-free) with no uniqueness theorem in existence until Lovelock (1971) -- Einstein's own 1913 Entwurf tensor is the live counterfactual, returning half the deflection and no Mercury anomaly -- and the coupling is MATCHED, not derived: kappa = 8 pi G / c^4 imports the measured G of the theory being replaced. Computed in the notebook (4 checks, exit 0) from named inputs: kappa = 2.076647e-43 SI with kappa c^4 / 2 = 4 pi G verified identically; Mercury's anomalous perihelion advance 0.103520 arcsec/orbit x 415.20 orbits/century = 42.98 arcsec/century against the measured input 42.98; solar-limb deflection 1.7512 arcsec against the round input 1.75, exactly twice the discarded accounting's 0.8756 arcsec; Sun's Schwarzschild radius 2953.3 m as scale check. Remainders at full size: G stands underived at this address; the uniqueness promotion belongs to Lovelock 1971, credited there, not to the 1915 paper; the 1917 cosmological term is CC-08's separate insertion; numeric exhibits run on modern named constants, fenced on the face. EXTENSION. Vacuum catastrophe NOT SOLVED; quantum gravity NOT SOLVED.