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_s3	0.2037 ± 0.0126	0.2691 ± 0.0139	-0.0169 (0.00098)	+0.0007 (0.52)
5000	lift_s45	0.2014 ± 0.0128	0.2663 ± 0.0148	-0.0197 (0.0015)	-0.0021 (0.73)
5000	lift_b0	0.2029 ± 0.0144	0.2684 ± 0.0144	-0.0176 (0.00049)	—
20000	hessian	0.2497 ± 0.0106	0.3335 ± 0.0099	—	+0.0427 (0.00049)
20000	lift_s3	0.2305 ± 0.0180	0.3095 ± 0.0191	-0.0240 (0.00098)	+0.0188 (0.0015)
20000	lift_s45	0.2219 ± 0.0083	0.2974 ± 0.0082	-0.0361 (0.00049)	+0.0066 (0.077)
20000	lift_b0	0.2177 ± 0.0146	0.2908 ± 0.0137	-0.0427 (0.00049)	—