If you wish to retain the same shift levers after the change you would do well to stay with another older Huret product. Older Huret derailleurs take more cable movement than other brands to move their cages a given amount. In this regard the older Huret shift levers have uniquely large drums. It is a system designed to work together. Mixing older Huret gears with non-Huret bits creates a measure of incompatibility.