The reality in the field from personal observation is that braces are almost always nailed with siding. Wheather that significantly adds much strength I don't know. And in our area of up-state NY many commericial type tf the braces where pegged. I would agree however that for the reasons you just outlined they probably wouldn't be worth the effort. But upon dismantling the pegs where apx. 90% intact. This frame was a coal and ice building that survived the great Carthage (NY) which leveled the city. It is a surprisingly well designed structure. In responce to hew to tighter tolerences I use chalk while hewing and choose my reference face and orient the log and hew this face to tighter tolerences. I don't know how any one could know how everyone hewed a log in the past. I then use a dry line during layout. I was not classicly trained as a framer (or typist)so many techniques I figured out or researched on my own.