Here are the steps to follow for the removal/reinstallation of the saddle leather:
Unscrew the tension screw located in the nose of the saddle until it is free, but without taking it out of the nose.
Remove the 9 screws and cups holding the leather in place and remove the old leather. - Present the new leather. Position it well on the crescent, the holes must be well in front.
Then adjust the position of the nose on the rails (the tension screw being completely unscrewed, the nose is now free and you can pull or push it to make it slide on the rails). Again, the holes in the leather must fall squarely in front of the threaded inserts in the nose.
Replace the 9 brass screws and cups. Screw them all in a few turns by hand to make sure that the screws are engaged straight in the inserts and that they do not force. Finish screwing and lock with a T25 key.
Do not force the screws into the inserts with a wrench or a screwdriver, as this may damage the threads.You may want to put a small drop of medium threadlocker on the screws (LOCTITE® Blue 243 for example) to make sure a screw does not loosen.
Tighten the tension screw in the nose until the tip of the screw appears at the back of the nose.