Trying to pull items out of the sifter via hopper/chute is a bit troublesome since the block has no separate input/output inventory and will simply instantly output e.g. the gravel.

To remedy this one could use a hopper with filtered slots, but that doesn't scale well with several sievables nor can you look at the block to see the items inside of it.

I suggest giving the player a single smart chute as a reward for this quest, so they can filter it on blacklist mode.

Currently the quest has no rewards whatsoever, and i think this would be a nice QOL:

you can use a Crude Storage Unit from Tech Reborn to auto pull items from the sifter. You can lock a CSU to only take one kind of item.

However, the most likely course of action we're taking with the sifter is removing it in favor of a solution developed in house.

Yes i did come across oierbravo/createsifter#30 suggesting the storage units, but just like the hopper you'll run into slot/side limitations.

Happy to hear a solution is being cooked up in house, consider this suggestion merely a bandaid solution then. 👍