Or use a webbing forgotten beast.
Of course, since webbing forgotten beasts are immune to webs, you have quite a conundrum. Try using cave-in dust to capture those.
They don't get stunned, IIRC, nor does demons.
Put a GCS behind fortification after setting up a whole bunch of cage trap, and wait for things to wander into sight of GCS and get webbed and snapped up by cages. At least that's the concept I sees.
have you tested this out? and anyone else see this as a viable solution? i would love to be able to do this without modding too much, and this sounds like a good idea, i could set up a gauntlet of fortified GCS in pastures and have an access to them to be able to keep them trained, would i have to have them trained as war beasts or just normal? the only issue i have with this would be all my dwarves would get caught going to my cave system
I've seen others use it, I've never bothered to test it myself, but as long as the creature isn't a webber, it works. AFAK it don't even need to be tamed either! Though taming is good idea if you're going to have them as pets
As for the trapped issue, forbid all the cage trap, seal up the GCS tunnel, have a tame GCS, use a loom to set up web gathering job on repeat ( I tend to disable them on o >w because of spam or dumb pathing ) and once it's cleared out, unforbid the traps and cages.