The KF Box is shown on the mounts page, I use it with my Mitu board: https://projectcedrus.com/mounting/
I don't currently have an adapter for Ketos but I would be happy to design and fabricate one for you. I do this for all of my customers who request something new, and don't charge them beyond the cost of machining the adapter: https://projectcedrus.com/adapter_fab/
Most of my customers are in the US, so I don't have adapters for many of the EU brands (Ketos, Horue, Alpine, etc). I have shipped a few masts to the EU, it's no problem. Happy to make new adapters to improve Project Cedrus for my customers.