How to stop a Mechanical Crafter from filling up with 1 kind of item?

I have limited knowledge of this mod and I'm struggling to build anything with mechanical crafters. I can't figure out how to stop them from filling up with 1 kind of item. For example I have Alex's Caves installed and I'm trying to automate Gunpowder production using the Sulfur from the Toxic Caves. Both my sulfur and gravel production work fine, but I can't for the life of me figure out how to control the quantity of items in the crafter. I've tried using the Threshold Switch with a Smart Chute but the signal from the threshold switch isn't instant and too much sulfur enters through the smart chute before it shuts off. What can I do?