Clean workflow ideas and some questions about a project!

:crazy_face::crazy_face:

I have a question. Im writing it here, because I know there are alot of knowledgable artists here. Im a concept art student, starting my last year after the summer.

Since I will be creating a workflow because I will do more of these…I was thinking of checking if this is a way to go.

Hmm, so.
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Im working on a furniture model, and it has poly limit. It is fairly organic in nature and I decided model it in Blender, I made the usual soft bevels, without edgeloops, made UV:s for all of them and then sent it to Zbrush where I will sculpt in the different ridges, folds etc. Then I will send it back to Blender and retopo it. OR creating a normal map out of Zbrush and apply it in Blender. The thing is that when it is done in Blender it is going to Substance Painter, where I will create another normal map that will be applied to the object in Blender. I have a small jpg image of the texture, so Im creating all maps and correcting it in Substance Alchemist.

This is my problem.

How can one use two normal maps after eachother.
Shall I create a normal map from sculpting in Zbrush and apply it in Blender?
Where could be the bottlenecks, are there other issues or tips?
Is my workflow possible?
Is there a better way to do this?

Im creating a workflow for myself, and learning tons of new things.