After carefully cutting it away from the molded assembly per the instructions, the unit requires a little bit of work before it can be installed on the motor mount. None of these steps are addressed in the instructions, by the way, but are pretty intuitive.
First the cavity for the engine hook must be widened with a needle file so that the hook can fit and move freely when the tail section is installed.
Second, the plastic 'flange' at the tip of the tail cone most be removed so that the unit can fit cleanly over the engine tube. I used a Dremel rotary tool equipped with a drum sanding attachment followed by a curved needle file to fine tune.
Now is the time to dry fit the tail cone to its position on the engine mount to make sure everything works.
If all is well, the tail can then be CA'd to the engine mount per the kit instructions. The main point to watch here is to make sure the top of the tail cone lines up precisely with the aft paper centering ring.
The final operation for the tail cone is to remove the unsightly molding seam lines.
This can be accomplished quickly by using an X-Acto knife as a scraper.
Holding the blade at a 45 degree angle, the blade is drawn backwards (away from the cutting edge) along the seam line. It effectively shaves off the excess plastic.
A little more work is done with some fine sandpaper to smooth things out nicely.
On this build I am not going to worry about any depressions along the seams, as the lines will later be completely hidden by 'Steampunk' detailing. If I were building the Protostar as stock, I would be using some thinned CA to fill the seams and sand smooth.