Looking at the postings/pictures from 2018 and there s no way I can see a double set trigger could have been used in that gun with THAT configuration.Certain parts require specific positions to be of use and when set triggers are wanted,here must be a specific place in relation to the lock/sear position.I have never understood the need for set triggers on any long rifle because none of them have sights worth mentioning.On most of these old guns the trigger must be set to cock the lock and that is a bad idea.The rear trigger holding the sear out of position is the culprit and unsophisticated lock mechanisms were common in that day and time but no reason to have them today.
Jim Kibler's fine late Ketland lock lock lends itself to single trigger because the sear/ pivot screw is a precise fit and and the sear rotates on it instead of wobbling around looking for a release point so no need for set triggers on the "Woodsrunners"he makes.
Just my opinion for what little it's worth.
Bob Roller