Notwendy - My 1956 model is a kissing cousin to my Avatar. They were made 2 years apart. I think they are very different from 158's but that may not matter when it comes to walking feet. In any event, it has a high shank. I've asked on the yahoo groups about a walking foot and was told by someone with the same machine that there is only one obscure model that fits it and it's quite expensive. So I use a darning foot similar to the one below and I limit myself to FMQ.
Someone gave it to me so I'm not sure of the brand name but I googled Elna to get that picture. I was also given a more traditional looking one with a visible spring but it didn't work right on my machine. It looked similar to this one.
Did I answer your question?