Don,
regarding the use of dogs I have found there is no universal answer.
For example, the logs I am hewing right now are all substantial -white pines yielding 10,11,12, and even 13 or 14 inch wide faces at 8 1/2 inch width. So these logs would require enormous dogs to be held in place. But their weight will not be overcome by a striking axe, if firmly seated in notches on substantial bearing logs.
For smaller logs, it becomes necessary to secure them somehow as notches alone might not be enough to hold them in place.
Personally, I don't like driving spikes into my neatly hewn surfaces, especially where they will be exposed to the exterior like on my current project. So I avoid it whenever possible. I also am not fond of the fact that dogs allow you to hew only one face at a time, which is a disadvantage in our style of working, where parallel faces are worked at the same time when 2 or more people are present.
