OK, you said you are inviting feedback.
I do not like the shape .... quite convex for the top .... slightly concave for the bottom.
Just my opinion, but I think both top and bottom should be slightly convex, the top a little moreso but not as convex as you have. . The cigar pen is quite a tricky one to get the shape right because all 4 bushings are different sizes.
The 2 biggest bushings are in the middle. . What I have started doing with the cigar is to first of all turn both halves "straight" to the size of the bigger bushing. After that I slightly taper to the size of the smaller bushing. . Do this for each half.
If you want, you can "taper up" slightly from the bigger bushing, and then "taper down" to the smaller bushing. . Do this for each half. . but you have to be careful to get the bulge right.
I prefer my first suggestion now, although I used to do it the second way.