I was looking at various on-line suppliers and had noted and bookmarked that one. NICE pistols you posted Dan. What "mods" did you fine were required?
I have found, in my limited experience that many of the springs supplied with locks are overpowered for the need and a judicious balanced lightening of the main and frizzen spring will continue to give sufficient spark-ability without battering the frizzen, or the hammer shoulder and jarring the pistol or rifle
Under powered springs. Springs cast from originals often lack the original arch and preload.
Late English locks will tolerate and may demand heavier springs than some more primitive Germanic locks will.
Many broken flints are the result of excessive frizzen rebound can be caused by a weak frizzen spring in some locks.
I rearched both main and frizzen springs on these two.
One had the tumbler hole drilled at an angle that required the hole be welded and redrilled using the bridle to guide the pilot hole.
The stop on the cock that contacts the lock plate stops the cock far too soon. So this needs to be filed to give a cock position as shown on the one in the photo.
Dan