I've been looking into this since my Assault has the same type of stick, only thinner. They hurt my hands to play for more than a minute or two.
I bought a Road Riot controller and the handles look the same to me (from comparing pics only, I've not seen another original in person since '88).
Anyhow, they are close enough for me. I'm going to make a adapter sleeve to put over the shaft of the crane-style stick shafts that are on there now.
Eventually I'm going to look at making an adapter or replacement shaft for the Wico bases so that it will have a leaf-style feel. I don't like the feel of the microswitches at all.
I'll start up a thread and get some pics once I get started with the project.
- JM