The Prestige/Riverside/Milestone twofers were my introduction to jazz back in the late seventies/early eighties. Two records for price of a single album. Most of that albums were OOP or simply impossible to get in the domestic market in Italy. Imports only. The BN catalog was poor, so the Impulse’s. The only Italian pressings widely available were the CBS/Columbia.
It’s all there in the Mingus’ Debut box set, with and without overdubbing.