[PlanetCCRMA] Legato slur and midi

[Robert Smith]

earching the web I  have seen it suggested that some midi synth engines
will produce slurred notes if you overlap them. I was thinking of
modifying a midi file to test this using fluid synth.
Before I do that can anybody out there tell me 
1. Is this going to work and if so how much overlap should be applied?
2. Is there a better open source way of producing this effect.
3. Is it possible to control the attack/decay in line?
If not I'll probably just hack a short midi file with a hex editor.
Unless you know a better way? 
Bob Smith