With only 7 boats and a wide line, sounds like the problem is just timing, not tactics. To keep it way simple, reach away from the actual line on port for not quite half the remaining time, allow 20 seconds (or whatever, depending on the boat and breeze) to tack, then reach back, luff at about 30 seconds left if you're early, keep on truckin' if you're on time, harden up to close hauled, and go for the gun. Boats that want the buoy/pin end, tack first; those wanting the committee boat end, tack later.
This is the old-fashioned Vanderbilt start. In small fleets, on a big line, it still works as well as it did 130 years ago. Sounds like you have enough room for all boats to be on the line, moving, on time, and in clear air, if they'll pay attention to the clock.