If you want to grind these out right now, with just Hallow's Throat released, I think there's 3-ish good options. First is the Bone Market, selling skeletons (value/10) or 49-voiced Warblers (100) to the Zailor for Warm Amber. Convenient if you've already got bones, maybe not if you don't. Second is the Laboratory research "Make a cartographical study of the ceiling", which currently nets EDIT: 690 Stuivers for ~27 actions (25.6 S/a) (originally wrote 340 for some reason). I'm guessing this'll cap out at 1250 Stuivers (46.3 S/a) once every Roof location is out, but that's months away. Third is going through Ecdysis and not taking a boon, which is 320 Stuivers for 11 actions (29.1 S/a), but you'll be gaining a lot of Nightmares unless you have good Shapeling Arts gear. Note that all of these give other items along with whatever converts to Stuivers, I'm just not listing them.