@Christoph-Hart Single time for fade into and fade out of legato sample is fine. Curve has been very important to adjust in the past, but I realize that's always been in the context of typical unaligned legato, where it might play in or out of phase.
So, going on the assumption that the phase-align-o-matic does its job, the crossfade should be linear as it is now, and probably doesn't need to be adjustable.