The "Proprietary"washers for the equinox are not round. I could make some I guess. The bolt with the washers is available in G.B.,
but I don't see them here in the US. I suspect the bolt is the same as for the Etrac, but not certain.
The washers can be made by cutting round rubber washers with a pair of scissors but I don't think they will wear out very fast. The bolt can be any plastic bolt of the correct size. I bought some for my CZ using wing nuts. They seem to work fine. Unless you are hard on your equipment you should never need them anyway. I only carry them in case of an accident.