RE: boring carbon prop
A drill bit can "walk" off center, especially in really hard material. Thankfully, model engine props aren't that hard to drill. I have alot of oddball sized prop shafts on various engines. There are times at the field where I have taken a drill bit, held it firmly with a pair of pliers and then rotated the prop by hand down the drill bit. Usually the application is for the odd sized little engines that have no true standard shaft sizes.
No doubt that a reamer is the most fool proof way to go, but I can not think of any time that using a drill bit has failed me..