Well, this is not as complicated as you maybe think.

What you need:

• An object with multiple subdivision (and of course sculpted details)
• UV for the object

This is how you do it:

• Go to Zplugin -> Multi Map Exporter
• Turn on Displacement
• Turn on Export Mesh
• Set the Map Size
• Make sure FlipV is tured on
• Go to Export Options -> Displacement Map
• Turn on: Adaptive, 3 Channels, 32Bit, exr
  Mid: 0 or 0.5 (in Maya you can use both)
  In this case you don’t need to adjust any other attribute. So leave the Scale:1, Intensity:0, 16Bit scale off, also you don’t need the Get Scale feature.
• Mesh Export settings:
  Turn on Quad, Mrg, Grp
  Quad and Merge are super important! (After the export check the UVs are merged, if not, run a Merge UVs command in Maya.)
  Turn off Tri and Flp
• You can save this presets with the Load/Save Presets button
• Click the Create All Maps button
• Done

In Maya:

• After you connected the texture through a Displacement shader check the Alpha is Luminance (File node) is turned on.
• Set the Alpha Offset to -0.5 if you previously set the Mid value to 0.5 in ZBrush.
• Set Color Space to Raw. 
• Of course you have to set a subdivision level in the Mesh node, Arnold Section, Type: catclark and Iterations.

Cheers, D