We generally figured no one would need one so we keep 1 of each in stock, most parts demand is pretty limited. I can order in another, usually all out of stock means is someone needs to package it for retail sale.
I am nervous that will compromise them structurally to a point the thread will slip or the part will break. I can have them in about 3 weeks but I think getting something custom 3D printed is a better path as I really doubt the integrity of the clamp will be the same with a section cut off.
What I might suggest instead is this, it is the same clamp, but you would also need to remove the hooks on top that hold the hose. All they do is block this part of the mold when they make them for the ORCA/AquaWind mount. It would be much cheaper to experiment with. It is hard to say, my experience with coarse thread is it needs more engagement to be secure, otherwise it can slip. https://shop.tunze.com/us/search?search=3154.555
It is a 4 pack so 2 packs will cover 2 units with a couple left over, these are pretty widely available, they are sold to hold dosing tubes and BRS and really most online dealers stock them.