I'll be posting pencil specs in a couple of days. As I e-mailed to Don, resources are in competition at this time. I need to nail down a few production specifics with some other folks, then I will be placing another material order.
Kelt, the pencils I measured varied (by different manufacturer) I opted to make it a little smaller than a Bic pen. A bic cap will not fit, the point extends through the end of the cap. An aftermarket clip may fit, can't say for sure yet, I haven't tried it.
I will give weight and length specs after the weekend. FWIW, the Ti pencil is significantly heavier than a traditional wooden one. An aluminum one would be also. It is considerably lighter than a steel one. This is not something you'll want to toss up and stick into a ceiling tile! As for sticking it behind one's ear, I have a crew cut and I have difficulty keeping the pencil in place. A friend grabbed the tipencil and stuck it under the band of the ball cap he was wearing leaving the eraser end out. He always works that way, pulling the pencil out and sticking it back with a speed that makes me wince. He stated he had no problem with the weight.
More info coming later, have a good day.