The Twizzel rig does not have the poles attached to the mast and looks to me to be a disaster just waiting to happen.
I've flown two head sails down wind across all three oceans, Atlantic, Pacific and Indian. I have never tried to use it to steer the boat and I doubt it would work with the normal tradewind seas which tend to broach the boat.
I wouldn't bother putting the second jib in a slot in the foil, just fly it tacked to the deck and with a tight halyard.
Have two poles attached to the mast with two topping lifts, two foreguys and use the sheet as an after guy. You don't want the pole swinging all over the place, only as a fixed fairlead for the sheet. Lead the sheets to a fairlead amidships and then to the winches, not to the stern as you would with a chute.
If you have the smaller jib to weather, you can even come up a bit and kill much of the rolling. Just ease that pole a bit forward and put a belly in that sail.
Practice in light airs until you've got the hang of it and it will become your favorite long distance down wind rig.