Brian was kind enough to send me an inner cap from one of his pens. I discovered that this piece is very close to the inside diameter of the hole in your standard Estie base.
I removed the stock insert from the Estie, and used some cardboard to wedge the inner cap in place. I realized that this will work! I realized that I also needed something to keep the nib from drying out, so I cut the top off of a CD spindle (prefect!) and shoved it in there.
A few notes:
If you do not use any insert, the pen will fit in the Estie hole; see the last two pics (but beware of scratching)
Not to get complicated, but the inner cap has a lip. This lip fits in the hole (by removing the chrome Estie ring). However, I found that inserting the lip into the hole causes the nib to drop too far down, and you cannot use the "cap" to keep the nib form drying out. So, I added the Estie ring back and this brought the shoulder of the inner cap above the surface of the base and also made enough room so that the nib can fit inside the "cap" in the base.
Sorry I did not do any darkroom on the pics... I just wanted to get them posted!
The pen is kept upright (and protected) by foam padding that I placed around the inner circumference of the, er, thing.