Not sure what you mean by "transition": here is the structure of the chamber strings legato violins: there is a fast and a slow version, with the difference being in the early part of the sample, the speed of change to the target note from the prior note. If that is what you mean by transition, then it is extremely short even in the slow version ( a fraction of a second). The full duration of all of the keyswitched samples of interval steps is medium length, about 4 seconds. There are also two sustained note samples of about 8 or more seconds, which you can get by keyswitches.
The only uniqueness in the legato instruments is at the sample start, the note transition from one note to the next, appropriate imo for passages at fast to medium speed. For long sustained notes, written as legato (but not played that way in real life because players have to change bows) I'd just use a sustained note at full nominal duration from some other instrument.
The only uniqueness in the legato instruments is at the sample start, the note transition from one note to the next, appropriate imo for passages at fast to medium speed. For long sustained notes, written as legato (but not played that way in real life because players have to change bows) I'd just use a sustained note at full nominal duration from some other instrument.