Ok, gonna post a complete start to finish "tutorial" on modifying the Sierra.
One thing to note, the "New" kits are assembled differently than the old kits, which is what was shown in the previous thread.
The major difference is that the nib is held into the nose cone in a tube, instead of the compression ferruel, and this tube is pressed into the center band, so ...
The following photos and discriptions are based on this, but easily adapted to the old kits.
You can tell the difference between the two kits by the length of the center band ferruel and the transmission, which on the new kits is the long transmission.
So, to begin...
http://i87.photobucket.com/albums/k1...d/IMG_1374.jpg
The new kits, note the long transmission.
http://i87.photobucket.com/albums/k1...d/IMG_1375.jpg
The parts you will modify and replace the black portions with your choice of material.
Note the short shoulder on the center band where the kits tube will ride, the old kits have a long shoulder, the new kits are short.
http://i87.photobucket.com/albums/k1...d/IMG_1376.jpg
http://i87.photobucket.com/albums/k1...d/IMG_1377.jpg
First, measure the parts you will replace. (learned that the hard way)
http://i87.photobucket.com/albums/k1...d/IMG_1378.jpg
http://i87.photobucket.com/albums/k1...d/IMG_1379.jpg
Using a steel rod or punch, press the nib out of the nose cone.
I am showing two ways to do this, either with a pen press or..
http://i87.photobucket.com/albums/k1...d/IMG_1381.jpg
Chuck it up and use your tail stock and a suitable taper, or a jacobs chuck, you can be creative here, you may be able to simply hold the nose cone with your hand and whack the rod with a mallet and pop it out.