Another question......... Did you use plain old tin/lead solder or did you used a silver-bearing solder?? And a request, if I might.....next time the camera is out, could you post a close-up of the "other" side of the clip....the edge where the solder line is located??
I, obviously, don't know what that side of the clip looks like so maybe it is not necessary; but it occurs to me that a "nicer" edge might be achieved by folding the clip twice. Fold 1/4 of the width of the clip towards the centerline from each side and have the "joint" on the back of the clip where it will not be seen. Easier said than done...I know...and maybe not necessary depending upon how your technique turned out??
One other thought.....if you used an acid-based flux to solder, there may be some green discoloration in the future unless you were meticulous in cleaning up after the soldering operation. If you are not already doing so and plan to make more of these pens, it might be wise to use a non-acid soldering flux.
Thanks.