a good place to start would be like 512. I pesonally don't really mind any small latency. When I am doing bigger orchestra work, I need to increase it to the highest on mine which is 1024. This still doesn't really bother me much, for some it drives them crazy but I can still work effectively and I get much more mileage before puter poops out. So It probally depends on how much VI's and what system usage they are drawing. This is when I am writing music. When I track, I cut that down of course
recording with virtual instruments - my guess is low buffer is not necessary to get low latency coz unlike audio, there is no incoming audio that is being recorded, converted (AD) and then played back.
Im pretty new-ish when is comes to midi etc. Got more involved in it this year. Before this l just handle audio and didnt seem to run into any of this.
When doing a track l pretty much start on drums etc, then go with whatever comes to me. So yes record, arrange on the fly. Then come back later mix it, arrange, move things around etc. Depending on how much time l have.
The track l have going at the moment always starts with an error, when l hit the space bar, after that its 90% fine. Error is "system held off too long, increase HW buffer size" Basically loses communication with my 002 rack. I hit "ok" and it comes back.
The track consists of the following VI's.
1 x battery 3
1 x Pro 53
2 x reactor ( different sounds)
3 x FM8 ( different sounds)
Stylus RMX - 12 midi channnels going
3 x audio ( with waves plugs on them)
So a bit l think?
In the playback engine pref l have:
HW/ Buffer size: 512 ( when recording etc)
RTAS - 4 processors
CPU usage: 90%
DAE playback buffer: Level 4