Here's some pics to describe the point: one from each source - Franz Joseph, the film miniature and my model.
You can see just how high up the side the impulse cowl starts:
Here's coroboration with the filming miniature:
And my model - which doesn't start even as high as the other two!
GaaH! you posted while I was posting! Still I think the original works better, Since the whole cowling or housing is deeper? Compare with the Casimiro and/or Sinclair drawings over at cygnus-x1. And if all else fails, tweak the hell out of it!