Very different and NICE !!! Great job Paul !!!
I have done some pens with oversize top barrel. To make the clip a bit better balanced, before assembly I put the clip in a bench vise (or Panavise, if you have one) holding it by the ring by the side of the jaws. The bent part of the clip stays outside, and will stick out about 1/16". This allows me to slip the shank of a drill bit of the appropriate size between the clip and the vise, all the way up to the ring. For this I have to pull the clip outwards a bit. Then I push the clip back to bend it at the top. Now the clip sticks out from the top of the pen a little more and is more parallel to the pen. Looks better and works better in a shirt.
If I get a chance I will take a pic and post it. If anybody tries it and can take a pic, feel free.