E1b — method-neutral H1 on gravity fields: mass coverage at matched spine length

Setup: 12 truncated-ZA boxes as in E1. Criterion needs no reference skeleton: fraction of all 128³ particles within r₀=3.0 vox of the spine set, spine length matched at 2400 vox. Note the spine budget covers only ~4% of the volume if spread randomly — differences measure how well spines sit on mass.

n_gal	method	mass coverage	band coverage (2<ρ<20)	Δband vs hessian (p)	Δband vs lift_b0 (p)
5000	hessian	0.2178 ± 0.0143	0.2860 ± 0.0149	—	+0.0176 (0.00049)
5000	lift_b0	0.2029 ± 0.0144	0.2684 ± 0.0144	-0.0176 (0.00049)	—
5000	lift_b1_sparse	0.1842 ± 0.0115	0.2425 ± 0.0133	-0.0435 (0.00098)	-0.0259 (0.0015)
5000	lift_b1_clean	0.1900 ± 0.0126	0.2504 ± 0.0141	-0.0357 (0.00049)	-0.0180 (0.0034)
20000	hessian	0.2497 ± 0.0106	0.3335 ± 0.0099	—	+0.0427 (0.00049)
20000	lift_b0	0.2177 ± 0.0146	0.2908 ± 0.0137	-0.0427 (0.00049)	—
20000	lift_b1_sparse	0.2166 ± 0.0141	0.2880 ± 0.0148	-0.0455 (0.00049)	-0.0027 (0.62)
20000	lift_b1_clean	0.2126 ± 0.0144	0.2828 ± 0.0144	-0.0507 (0.00049)	-0.0080 (0.092)