i’m not sure what the holding power is, but I just put one on my cast iron table saw top and pulled it off. It felt like it was probably 50 or 60 pounds to pull it free. But that’s just a guess.
Sorry for not responding earlier. I have been out of tractor bidness a few weeks thanks to a case of covid. OK now and happy to supply any details you wish. Tube size? Connection to Kubota brand sunshade? Mounts for lights? Electrical supply from battery to fuse box on one post? Rear view mirrors? Just tell me what you want to know about. FWIW, my pics make it clear I need to clean up wiring around the switch box - all the rest is in strong wire loom and tucked away well.