I've just started grinding Management Skill.
I am fishing (R16+1) and using Storage (R15+1). I ws processing massive amounts of fish and the skill level was only climbing slowly.
I did a quick experiment. I processed 5 Peto (R4) first individually and then in one batch. I got much more Management Skill EXP doing the storage one fish at a time.
It's laborious but the ration was 4 exp to 10.
(Incidentally with Management at R2 any fish at less than R4 returned no EXP at all).