The art of timing messages.....
1. First of all, you need to rund FS2_open AND Fred simultaneously. It speeds up things pretty well.
Check your fs2 launcher for the "run in window" checkbox, in the feature list. I think its is listed under DEV TOOLS or something like that. Change in fred, save, goto FS2 and just restart mission , and you can instantly check out the changes you made.
2. Messages come either as "SEND MESSAGE" or as "SEND MESSAGE LIST"
If you are not afraid of loosing overview it's more convenient to use SEND MESSAGE sexp, chained. Use the MESSAGE LIST only for small portions. It's faster to copy/paste the SEND MESSAGE sexp and to make the small changes, and you are more flexible if you want to add/remove messages inbetween.
3. Voice Synthesis has a drawback. As IPAndrews told you, you DO get an impression of how much time your chatter takes, but it is only an impression. I found my actors being faster than SAM.
4. Especially when you use cutscenes you will want to be very precise with timing. Cutscenes are a very able method to improve gameplay.
First of all, the cutscene itself is a small highlight on its own.
Second, ever since cutscenes use exactly predefined camera positions and angles, you can use a cutscene to change the mission setup. For example, you can use cutscenes to mask the use of the COORD MANIPULATION SEXPs. Instead of letting the player fly all the way to the next point of interest ( lots of km ) you can just change the positions with a sexp. When done with a cutscene, you'd get a wing commander-like autopilot cutscene or something similar, and it really helps keeping the gameplay fluent.
