I found the titan extender was not thick enough and left the fan duct too far behind the nozzle - so I thickened it up a little.

There are two mounting holes to the backplate, which are the top and bottom holes.Then there's three adjustment holes for the fan duct height. These are designed to accept the little brass threaded inserts like the rest of the backplate. I recommend using the top and bottom two adjustment holes. The third hole in the middle was probably a bit overkill, but I can't be bothered removing it.

The part is in the photos, printed in green.

Yes - i'm aware my fan duct has a hole in the end of it - broke off as I was getting it off the bed.