Mt. Lily's Permanent Reissued Phase 2 Expert map gives over 10K gold every run, plus 1k+ seeds.
Dunno what you ran.
And 12-5 is an Ampy map, not a Manyu map. Many cheaper maps to spawn an 80 Stam SG, but it's still half the stamina to spawn one over an Expert event map. With only a few hours left to the event you'd only really farm that for LCs, wouldn't you?