I had a long response type out, and then decided you might take it wrong. I had not heard of bellvilles on a barrier strip before. Its an interesting idea. In this case I'll go with function over form and use the wire nuts in a J-box that might never be opened again for the entire life of the machine. I might even go so far as to tape the wires together to act as a strain relief. LOL. Old and simple methods work.
It might be a "prettier" option though.