One of the problems I find with my clock build is that the 'Nome pendulum is darn heavy!  Lifting 7 kgs of cast iron with a delicate suspension spring on top into the case and placing the upper chops onto the bracket can be a bit fraught.  The other day in Lidl I came across a pack of two of these:

They are stout reinforced plastic pouches with an inflator bulb attached, intended for jobs like lifting doors into precise position.  Put the pouch under your heavy object, inflate to lift into position, fix then deflate.  Described as "air wedges".  I've seen similar in my local tool shop at ~£15 each - I doubt the Lidl box of two was even that much.  So, put a wood block on the bottom of the case with the wedge on top of it; stand the bob on the wedge, inflate.

Once the chops are above the bracket, carefully tilt pendulum back until in correct position, then deflate to leave bob hanging in place.

Hope this suggestion may be helpful...