Shake test!
Secure everything as above.
Add a string to the pendulum lock to be sure it cannot move.
Give it a gentle shake while looking close to make sure nothing moves.
Get a box that closely fits the clock, wrap clock with newspaper and tape tight, paper to paper with the tape or to Glass only.
Place in first box and use cut and fold cardboard to make corners to fill the corners to insure no pressure on any flat surface, only support the frame.
Add spacers until it is a snug fit.
Once it is snug in the first box tape it shut.
Again, gentle shake to feel for movement.
Now get a bigger box, heavy wall is better, and create a lot of cushion between 2 boxes, crumpled paper or foam.
Equal space on all sides, 3 inches minimum.
The material needs to allow movement on impact but retain shape.
When full close and tape shut, shake the box and feel for any movement.
If no movement you should be good.
Print "Delicate and fragile" "do not drop" "this side up" or other such warnings on standard paper and tape them to the box.
Insure for proper value.
Insist on SIGNATURE REQUIRED, make sure the carrier indicates on the box and or in their system that someone at the other end must accept it and not just drop on the porch.
Ship to someone's place of work if possible, usually commercial route gets delivered earlier in day by usually not contractors.