Well, without even one compute terrain the one with the horseman rendered in half an hour in RT. PT took 4h though. Still have to check differences.
I'll tell you guys (or what's left of the 'community') a little something I just discovered yesterday, and which you can add to your documentation
Fake stones have an inbuilt way of computing lateral displacement, which I kind of knew but never really explored.
So I took some huge fake stones and just added some lateral displacement into the surface imput from a mix of PF and image map greytones. As simple as that.
I'm working on another cliff where I raise ground to a steep side, clad it with stones, which can have the lateral displacements. Hence no compute terrain needed.