Hi,
Most best quality and fully evolved English dueling pistols had set triggers, which were called "hair" triggers by many at the time. John George has a nice diagram of a typical pistol set trigger in his book on English pistols and revolvers. Rolf's set from Blackley's is similar to that drawing. I had the privilege of handling dueling pistols by Innes, Joe Manton, and a third maker (I don't remember the name). All had hair triggers and were of the late flintlock, half-stocked styling similar to Runastav's project. Without exception they were exquisitely made. They all had heavy barrels that were almost straight and were horribly unbalanced. Indeed, the Manton pistol was the worst, and I greatly disliked the feel of it. When I built a pair, I chose a pair of 1780s Wogdon's as my models. For my tastes, they make the the later heavier dueling pistols feel like hockey sticks in comparison. In my opinion, the early and mid-career fullstocked pistols of Wogdon, Twigg, and John Manton are the best of the best of the best with respect to appearance, feel, and handling. Of course, I am biased because I like lighter pistols and I have relatively small hands. Someone with large hands may prefer the heavier style. I did not not include hair triggers in my pistols because the pull was crisp and light without the set mechanism and makers sometimes did not include them on the earlier dueling pistols.
dave