Couldn't edit my post ...
Forgot to add some cliff notes to hopefully save some pain and frustration.
Press the Twist Holder into the lower barrel
before doing the next step (don't ask how I know)
Now the fun part. Grind, cut, mill, file off the the ring off the Twist Holder so that it is flush with the tube.
You will know when it is done because the whole assembly will slide into the Sierra Tube and rotate easily.
BLANK:
Measure all the parts of the regular cigar pen and cut the blank.
I cut the blank on the long side at 4 3/8" for the Curly Maple as the first one was a tad short and I like the look of the long wood.
Drill a 10mm hole in the blank for the cigar tubes.
Now take your 27/64" drill for the Sierra kit and measure the length of the tube on the drill bit with masking tape.
Pick one end for you nib and drill the wood out with the 27/64" bit plus a little to square the blank up.
Push potato, play dough or wax into the tubes and glue into the wood with CA or your favorite glue. Mine is Sumo at the present time.
For bushings I was originally taking a cigar bushing and wrapping a piece of 1/8" masking tape to take up the difference between the Sierra tube and the 10mm hole of the cigar.
Johnnycnc made me a special bushing with the cigar nib diameter and the 27/64" of the sierra tube.
Assemble the kit. Now everything just slides into the wood from the bottom.