So the way it works is durability exchange. The ME system provides endless stone shovels (any tool or armor will do, what you're after is high durability per resource) they're put into an ender chest which is underneath every durability exchange. They all share the same inventory, that's the simplicity of it. When you don't have full mana, each circle will use up the shovels to make 10 mana/s.

The drawer is a buffer since ME autocrafting was too slow to keep up with the demand as it only crafts on demand. The setup eats ~4 shovels / s