The typical problem with those triggers is the rear trigger cam riding too high in the un-set position.
It's caused by the triggers leaf spring pressing hard against the rear cam. This is how the the set triggers work, I mean it's the leaf spring that drives/makes the cam work.
There is a small screw behind the rear trigger that allows you to adjust how far the leaf spring travels.
There is a balancing act with the two adjustments of that spring, the first being the spring tension itself which is simply the mounting screw for the spring,, you want the spring to have enough tension/power to drive the cam,, and then with that small screw I mentioned adjusting how far down the spring moves against the trigger cam.
Then of course the screw between the triggers adjusts the hook-up of the set triggers in use.
So there are 3 adjustment to the triggers plus the one for the tumbler that you show in your photos.
It may seem complicated but is actually simple in the practical mechanics of it,, you can tune this set-up for a super light, crisp fast breaking action with these spanish guns.