Hello all i have never really had any luck with height maps in Toolbag, i dont understand how they work. They eith ballon out my model or make my model look like a bundle of thorns, i normally use the Unreal 4 PBR set up for texture export from Substance Painter and use the Unreal 4 Material set up in Toolbag.
Here's how marmoset reads height maps
Here's how painter reads/uses them
Something like this
Substance painter/designer do put out a height map. They can also display it.
You display it in marmoset by putting it in the displacement section and turning on subdivision to the max. (or lower- experiment a little. but max is always most accurate)