The nuts are welded to the red part on the inside.
You could push a smaller screw through it or drill new holes.
I have it on a wooden beam and have screwed an aluminium plate (15mm) to the beam and drilled holes where the nuts are. So I first screwed the plate to the beam and then the winch to the place.
Hello, I slipped an old rectangular Thule roof bar into the collars and fixed it to a ridge beam with two spansets. I couldn't make any holes. It held 100kg easily. Cable a bit too short (2m?)
Mounting in other positions (e.g. rotated 180°) is not explicitly mentioned in the official documentation. The instructions describe installation with two mounting brackets on a square tube, whereby the anchoring should be checked by a qualified technician. For specific installation variants outside the described application, we recommend consulting a specialist or contacting Einhell Service.
Note: The maximum load capacity and lifting height vary depending on the use of the guide pulley (250 kg/5.7 m with guide pulley vs. 125 kg/11.5 m without).