For very bad scavengers (int <60, survival < 20 and masterlove (affection) below 60) the yield will be between 0 and 2 merchandise, but most likely zero, unless prosperity is high.
For very good scavengers (int >59, masterlove > 59,Survival>59), with the Scavie-trait, the yield will be between 6 and 12 merchs (unless prosperity is high).
This means, considering the max yields for Scav-duty in v8.23c for the different npcs (mercs), that only Ansel, who could bring in 16 merchandise (with high int), and the Space Marine will bring in fewer merchandise in the current v8.3h version compared to v8.23c.