Building a bench fitted to my body, not a generic adjustable one.

Use case:

* Chest on the center pad, knees and shins on the two rear pads, arms on the side pads
* Fully restrained. No movement is the point
* Heavy casters so my partner can roll me to the bed for oral, then rotate the whole bench 180°
* Two machines at the same time: a Fredorch F21S clamped to two 25×25 rails behind the hips, and a Venus 2000 hanging in the gap from four simple eye clamps
* Bottom plate is the parking spot for the Venus 2000. A drip tray is planned, not drawn yet
* Breaks down and goes into a closet

Frame:

* 40×40×1.5 mm steel square tube
* 25×25 mm rails for the F21S
* M8 through-bolts everywhere, 9 mm holes
* Cross bracing on the sides
* All joints are 3D printed PETG (2-way / 3-way / 4-way). Thick walls, 36 mm sockets for the 37 mm ID tube, about 0.5 mm clearance per side
* Same black PETG for the machine clamps. Steel bolt, captive nut in a 13.2 mm hex pocket, printed cap over it

What I want:

1. Are printed PETG corners with through-bolts enough on a 40×40 frame if someone is restrained on it for a long session and a thrusting machine is running on the rear rails?
2. The 25×25 rails are cantilevered. That is the part I’m least sure about. Clamp design is in the photos.
3. Anything you’d change before I commit to \~26 printed joints.

This is the prototype I will actually lie on. CAD attached. Be blunt.

Custom 40x40 steel bondage bench with printed PETG joints and dual machine mounts — sanity check before I print the rest