Just my two cents, which may only be worth one, but don't expect any refunds...

The way most people seem to use normal maps with Poser is as a displacement map, using a texture map that has been converted into a normal map, which basically does nothing other than add a sort of bump map conversion of the original texture map. And, given how Poser users these, there's really not much of a point at all to using that particular sort of normal map. You're probably better off tweaking a displacement and/or bump map, as BB suggested.

This is sort of alien to me. I see Poser bump and displacement maps as 2D maps derived from an image file specifically designed for that purpose. A normal map, on the other hand, is something I've always associated as being generated by geometry, not textures. So, when I see people "creating" normal maps by shoving the object's texture map into Photoshop or another 2D app, I sort of scratch my head. "There's a bump/displacement channel for that... what's up with that?"

In the OP, it looks like an attempt to generate "something like" a normal map using displaced geometry and different rendering angles. That's a bit closer to the mark, but it may not work well, as has already been addressed. (I have no idea what Poser's capabilities are above PP2012, so if later versions can generate normal maps or have some more utility there, potentially allowing them to be created... I'd be interested!)

To me, the best use of a normal map is simply taking the original object, increasing its resolution/density, fine-tuning detailed geometry and sculpts, then rendering the high-poly version of the object in something like xnormal, resulting in a high-res normal that you can then place in the normal channel on the lower-res model, getting a potential two-fer :) in memory footprint, but with the added benefits of a normal map.

In other words, I am confused by the idea of generating normal maps from 2D maps, almost always the original texture map image, then trying to plug them into the normal channel as if that was going to do much more than a regular bump map. (Just wanted to clarify - That doesn't appear to be what the OP is doing, since they're combining displacement, which effectively increases the object's geometry, making it more useful in generating a normal map.)

On "Baking" in Poser, which was mentioned in the OP. CAN some standard version of Poser bake procedurals? !! I imagine the game-dev version can or should, at least, but can an out-of-the-box version do it? Again, I'd be intensely interested if it can OR if there is a script/way-to-do-it in Poser. (I know Carrara can do it, with a plugin.)

Oh, on tangent and object space, this is a pretty simple explanation: http://blog.digitaltutors.com/bump-normal-and-displacement-maps/  And, some more technical details in this answer: https://gamedev.stackexchange.com/questions/31499/what-are-the-advantages-of-tangent-space-normals-over-object-space-normals