We go with a preventer when running downwind.

When we prepare for a jibe the first thing we do is reef the headsail about 30 percent ( we run a 150), loosen the preventer, turn the boat almost directly downwind while centering the main. Make the turn through the wind and let the main back out on the opposite side. Finally, re-rig the preventer.

At the same time the boom is going over one of us releases the headsail sheet allowing it to move across and set it on the opposite primary winch. When everything on the main is completed including resetting the preventer we allow the headsail to unfurl and set it to the main.

If we're running a asym. we douse it with the sock. After the main is set we rerun the asym. lines and pull the sock back up allowing it to open.

Damn, that's a lot for two people to do to make a simple jibe. The good part is that when cruising you don't jibe often. 40,000 lbs of 50' boat and two people forces us to go slowly and deliberately.