i believe the one for a sa200 is a k384-1, then theres a newer version k-623-1. Check ebay
Im pretty sure the 200 and 200d cv adapter is the same, they are easy to install, you do have to take the shield off the gen. housing and run a cable and a thermal switch that attaches to one of the brush holders. the mounting holes for the box are already there
I have a sa250d with a cv adapter and it works great, the biggest wire i run is .072 flux core, and im close to exceeding the limits of the sa250 at that.
A 200 should be ok, but it wont take too much to overload it