Personally, I'd suggest going with vanilla first. Sectorials add a whole new level of complication that newer players just don't need when they're trying to take on that learning curve (and it's a steep one, trust me.) As far as synergies go, a lot of it is just experimentation and experience. I'm not a CA player, so I can't offer any specifics. You learn about synergies and piece trading and stuff like that through playing games. Honestly, if everyone is new, don't do escalation leagues. Just play small games until everyone is comfortable. Start out at 150 points. Play a dozen games at that level. Then move up to 200. Then 250, and finally to 300. It can be overwhelming to be diving straight into a 15 order, 300 point list where you have to keep track of so many guys with all their different rules. Start slow, play learning games, experiment, and practice, practice, practice.