Ok some updates !
I built the conical engine bell masters for the secondary engines.
I built it myself to save some money but wasnt sure about the result... The first attempt was a disaster, it was way out of shape (couldnt get a perfect round shape lol).
So first I built this :
Then wrapped it with 4 layers of 0.5mm styrene. The 2 inner layers are shorter to create a lip.
Eventually I ended up with that :
I was very happy ! Almost perfectly round (Im sure it's rounder than the original

), very strong and light.
Then I cut those 9 blocks. None of them are perfectly identical :
On the round plate, with some greeblies :
Dry fit :
Now I had to built the inner tube. Of course I didnt had the right diameter (33mm and I wanted 35.6mm) so once again I layered some styrene around it !
Everything glued in place, ready for primer !
Light coat of primer (I had some air bubbles created at the edges of the lips, going to sand them).
Almost ready to pour rubber on it !
I'm very proud of it, when I started this part I have very little hope to be successful but I think it is !