If truth is that also upon which something may be built, to speak against the common will to truth which we know Nietzsche and Deleuze have discredited, then that upon which the most truth may be built would perhaps be some ideal range of un-truth mediated by truths sufficient to secure the operation's effect toward that which is or must be the goal/end of the process-- truth as tracers in the shadows, lines that point outward toward horizons.
What would be the goal-end? Likely whatever it is would appear in the form of greater abilities to will the un-true, toward... Let content dictate velocities.
The higher being cultivates un-truth in himself in order that he may better approach reality and the reality of his truth's effect, its power. (Nietzsche approached this by calling it the master morality.) Likewise, all men appear to instinctively follow or follow from this method, albeit much more narrowly and without what we call intent (i.e. without that will which has grasped toward its principle extant to its need).
What key that would unlock a world of reason, than that which affords reasoning consciousness access to its own greater nature and consciousness; a "will to will anti-will(s)". Anti-will is useless or worse, without the (more) express will to it. This is Satan-becoming-God, through sheer power of "desire" (desire as either the lower emptiness-directed anti-will or the higher will-to-anti-will whose emptiness has been marked off by laying down railway lines toward infinities, thus "willed" indirectly -- form as the indirect expression of the force of content/s).