How to place uv islands in multiple UV sets (UDIM)

I have a complex model and I have unwrapped it using texture atlas. Now I want to place uv islands in two uv sets (UDIM - I’m planning to use two 4096x4096 texture maps on this model)

A single object of the model cannot have uvs on both uv sets (please look at the example). This model have hundred of objects. So placing uv islands manually on both UV sets is not easy. Does anyone know how to place uv islands easily while maintaining the uv scale according to the objects? If you have other ideas about this please let me know. Thank you.

Here is my model.

Here is the current uv map

Here is the example

There are some different approaches you could choose to get there…

You can for example create a double width image before unwrapping, and after unwrapping and moving the islands that stay in the middle to either the left side or right side, delete the image and scale everything in the x axis by 2.

Or you can select the islands for the second udim, pack them, move them in the x by 256 (in case you dont have any image yet, if you do then you need to move by the width of that image). Repeat for the other islands, and if needed ‘average islands scale’ to keep areas uniform.

There probably more ways to do it… maybe someone uses other methods.

Thank you. Do you know some unwrapping plugins for UDIM?