Jean asked for more info on the modification to the AVL tension box. Remember that cutting the top off the reed will weaken it and leave sharp pointy bits that will scratch unwary arms and hands.
The top photo shows the gate partially open. Doug made a wire that pivots on the closed side of the box and fits into a hole in the base of the tension box.
This photo shows the gate closed with the wire in the hole in the base.
This photo shows the tension box from the end. You can see how the tines have shifted and moved at the top but they are still in the correct alignment at the bottom, which is where the yarn travels. The wire is anchored and swivels around a nut/bolt. The gate is closed and you should be able to clearly see it near the base of the reed. Click to biggify.