I stopped using original gaiters. They don't last very long.
5 years ago i used an universal gaiter, just like Oetker.
I made an expantion tool to slip the gaiter over the tripod.
(hamer is not part of the operation).
First soften the gaiter in hot water, and with a bit of percuasion you can aply the gaiter.
I shortened the metal can, and secured it by hamering the edges.
A big downside of what i did is that the tripod is not held in place. (because i cut the end of the can off)
Mounting the trailing arm is challenging because you have to compless the spring in the tripod all the time, during handling the trailing arm.