It usually resembles pendulum movement (because by reacting only to location and speed, your simulation works almost like gravity does).
So if i want to keep hovercraft at 1000 units above, if its below i push it up, when its up i push it down. Task is to find optimal force that does not push too hard, and instead approximates strength so hovercraft stops at 1000 units. That is very common problem for automation and control theory, it is most basic stuff (because we have linear function here), but gets very complicated when you want to find optimal steering. I could even find formulas, but those are some Laplace functions, converting them into script that calculates discrete response is something i do not want go back into. I hoped you know that automation stuff, your response looks like your nick is not far from truth.
It is not only problem with hoovercraft, first time i faced it was when i wrote AI for spaceship (restrained only to 2d plane for easy testing). I could not make spacecraft stop at destinations, It always went into some circles around, because my script was over-steering with forces applied. Then was that French guy having same problem with his game, it tok a while for me to realize its not camera problem but his pawn is rolling madly. Now this topic about hoovering craft, that need 3d stabilization over some track, which is most complex case so far.
I probably will tackle it again when i code hoovering drone AI, but knowing math behind it, looks like quite challenge. Unless i find formula or algorithm for finding best response.
I have some glimpses of memory how steering graph force for this should work (x=y^2) or something very similar, i kind of remember shape of graph.
So solution may be quite simple: use blueprint function node, find that graph on internet, recreate in unreal, and apply result as force.
This is something like is needed here: http://blog.wolfram.com/2011/01/19/stabilized-inverted-pendulum/
And this is math, but it gives me shivers when i look at it.
Thinking more about it, this topic case needs inverted pendulum stabilization to stay on track (and do not do random barrel rolls), and keeping distance from ground probably can use same formula.