I recently got a Van Brunt FB137A and am reviewing the manual on operating and setup. The manual references setting the seed doors for various size seed using a hooked tool. I briefly looked at my doors and found they are not all set the same and everything is so grungy I cant tell for sure which slot they are set in. Tomorrow I will clean and adjust tomorrow but have a question. How do you adjust the doors? Does the tool hook in a hole on the door, or does the the tool just pull the door forward in the slot? Do you push the door rearward to change slots, then pull forward to engage a new slot? The manual didnt go into depth on adjustment so that is why I have questions, and can it be done by grabbing with needlenose pliers?