We have introduced LASSI[r,q], a systematic hierarchy of post-LASSCF methods in which the CASCI limit is recovered in the limit of large r and q. Test calculations on the spin-state energy ladder of a triiron compound Fe 3 and its aluminum-substituted variant AlFe 2 show that LASSI[r,q] qualitatively reproduces CASCI for r = 1 and q no greater than 15, and usually as low as 7, leading to a compactification of the wave function by several orders of magnitude.