As I guessed I would not be able to finish the bonus completely, but at least I got the arm weapons for my Dominus knight built, which was my real hope with this, and as a bonus for the bonus I slapped on the base greens.
I did some minor modifications to my original idea with the rebuild and made the barrel cowlings a bit smaller as well as the reinforcements of the lower shield. Apart from that it has mostly been a question about closing gaps and making things fit together. Over all it is perhaps not the cleanest build but at lest it got done and I can move on to other things.
One thing I noticed when trying on the arms on the already finished body was that I have sculped some cables around the arm sockets that prevented me from mounting the arms, so I hade to take the scalpel and trim the cables down, not the most pleasant thing to do to a already painted model but it needed doing.
Now I just need to paint these and I can call the knight done.