I have just acquired a new Mac computer. Several years ago I did the same thing and at that time via help from Camera Bits, I was able to copy a specific file (Photo Mechanic related) from my Main computer to my New laptop that had all my current IPTC data that I had setup. This resulted in my not having to refill in many of the data fields, etc.
Currently, I cannot recall the name of that file nor where it is located in my main computer directory. Hopefully someone may help me.
Don J J C