Couldn't you measure what you currently have and take it to a machine shop to make new ones a little bit bigger? Be sure to measure the hole sizes in the rack.
Most machine shops want to build "a run" of four pieces, have them make five and you will have a spare. They could cut one and let you try it out and adjust from there. Machinists know their trade and they will know what you want.
My machinist buddy builds me things often and at a fair price.
Once you figure it out, let us know and perhaps others will order with you.