Just an update:
I received the end clamps/covers and test fitted them.
As one can see, the -12AN on the right fits over the ARC silicone hoses to include the "hump" in the inlets/outlets of the tank. However, because of the size they rest against each other whereas the pictures look like there is a bit of wiggle room between each clamp/hose.
On the other hand, the -10AN on the left are too small to fit over the humps, only covering <5mm of the inlet/outlet. Unless the owners drilled out the openings of the clamps to fit, these wouldn't work.
I contacted the owner of the first picture (RJM strut brace) and he said he'd get back to me but that was earlier in the week and I've yet to receive a reply. I'm going to go ahead and order a small piece of the -10AN and -12AN hoses and test how they fit. That should be the final indicator on whether the -10AN should be drilled or to just use the -12AN.