Don't use 'Custom' pen sets.
When you modify a pen set, make sure you save it as a named pen set.
You will also have the option to "Store As" and then you can overwrite an existing pen set.
In you layouts you then make sure that your drawings are using that named pen set.
If they are using the named pen set that you have overwritten, they should update automatically to the new pen colours and weights.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11