I think I've finished. I've based the ball socket on a diameter of 4.80mm according to Iriorne's measurements. If the ball itself it 4.80mm then it may need to be sanded down slightly and lubed if it's still too tight.
I hope the socket is alright, took me ages to get it right. It's in the same place as the reference pictures that were provided, so hopefully it's the same seeker mold you're using otherwise I've got more work to do.
The ears only stick out maybe a mm or so, but not very much so it shouldn't be too difficult to make some adjustment on the mold as Iriorne suggested.
I had to square the rear of the helmet off so that the ball socket would fit properly, but I tried to make it as little ugly as possible.
Anyway, here's some pics:
Cutaway image with ball joint in place. I have included two stems to show the 2nd position with the head folded down during transformation:
Close up of ball joint in place:
Side/Rear view:
Size comparision:
(sorry Iriorne, that's the best I could do with the image you provided for now. I didn't want to spend too much time on the reference image).
And because I was curious, here's one with colour:
Here is an animation of the head sculpt rotating so that you can get an idea of how it looks:
http://www.youtube.com/watch?v=kAtaM...ature=youtu.be
And just for fun, I was playing with the chrome effect:
https://www.youtube.com/watch?v=GiCe60scG1Y
Anyway Lancalot, let me know if you're happy to go to print.