Not sure if the "blue" demons are still there but the quest arc from the gargoyle queen for the 1st book, those demons are great for gains and a glave outranges their spells
The real downside to the acid slug approach is the tactics is really low. Think its 50 even and your tactics will stall out at around 90.
You can always soulstone taming on your thrower for a bit and train on a fresh tamed Cu 40-80 then a gmed cu from 80-120. Heals itself use an NPC boomarage for lower damage and stand at max range. Shouldnt come close to killing it.