You also explicitly asked about what is roadlegal. I can't say anything about that, because I don't know the regulations in your country.
In addition to the basic legal regulations, sometimes we also have some binding specifications in the vehicle documents over here. Primarily concerning the free movement of the wheels in the wheel housing with the chains. Whereby, well, common sense says that they must be absolutely free to move. I would always try this before using the chains.
From my experience, it's generally a good idea to use high-quality snow chains that can be installed relatively quickly. For a heavy off-road vehicle it may be something better. Here is a practical tip. It's best to practice putting on snow chains at home in a warm place. In cold weather and driving snow, this can otherwise be an annoying affair. And please remember using work gloves and take care of your safety, especially when mounting on the side of the road. Think safety, please.