Remix of MK3S- Frame Tray from akamaka if you have also mounted the squash balls for vibration and sound reduction from Liouma https://www.printables.com/de/model/227986-squash-ball-feet-the-most-efficient-system-for-pru. Cause of the mounted squash balls, there is less space for the tray holder. Thias version fits, even if you have the squash balls mounted. According the hint of akamaka, a small hole was made in the hook just in case. If required, you can optionally install some filament or a small screw to secure it from falling down after the tray is mounted. But in my case, it fits very fine without securing it in addition. Many thanks to akamaka for the original tray!