These are the two simple spider dungeon grinder designs I came up with earlier today. One is for normal spiders and the other is for cave spiders. They are both exactly the same except the cave spider design has 3 cactus pillars because cave spiders are smaller and can fit between the other 2 without damage.

These two designs use hoppers to collect the string instead of a water channel. This allows it to be much more compact, simplified and it makes it less likely that string will get destroyed by the cactus.

In the included schematic file, you will find two schematics, one for each design.

I've built the cave spider version on my survival world so I know it works. I added a door to it on my world for maintenance but otherwise it's the same. When I stand at the chest, the spiders all agro at me and die, lol. I don't know the exact drop rate but in about 2 or so hours you could probably fill up a single chest. Mine was almost full at around that time.

Additional Notes

Texture pack: Pixel Perfection