I tend to take the middle road with my gambits. On my North America FFXII, I have every character set up in such a way that buffs are automatically evenly spread, and every character has healing/status affect recovery abilities. This means that if I so choose I can sit back and let my characters to work for me (Which I did for Hell Wyrm aside from two points where I took over for some heavy duty healing hijinks), but more often than now I just take control of my party leader and manually control his actions while the other two act as AI Support.

On my FFXII-International Zodiac Job System, Gambits are a bit more simplistic, since everyone has a specific class/role. It requires a little more involvement since you can't build three all purpose Rape Machines(Tm) and have them handle everything. Normally I only manually control my tank so that I can draw stuff away from the mages who deal my damage, and handle healing manually via a red mage or other character so that I have a greater deal of control than I would if it just auto ran.