Best way to model details from low res model's textures to high res model for normal maps?

Hi folks, I’m currently modelling out a hover platform for my game. I’m done with the low res model, uv unwrapping and texturing. The issue now is I have textured some decals on my low res model and wish to apply normal map to make them stand out via a High-Res model.

Decals circled in red are the ones I wish to model out in my high res variant:

How do I know precisely where to bump out without messing with the textures? I need a way to trace over the textures of the low res model or if there’s a better way please let me know.

I could take the cheat route with photoshop and the nvidia filter but I wish to do it through high-res model baking instead as the results are much better.

Any help appreciated!

could use a mask to cover what is not needed in the UV map
then bake your high res map and use mask with mix shader

happy bl

Ever heard of floating normal maps ?
Just copy that polygons which you want to refine, do some dividing to match your tex, maybe retex to be precise and do some geometry refinement, seperate to new object and build/bake your new normalmap…