Help with cooking tonights meal!?

I would say a low-ish heat, say 150C. If you use three hours as your guide you will probably be fine. You can always turn it down and leave it in the oven if its done. Feel confident, you cannot really overcook these things as you are aiming to completely soak the meat in the juice until it falls apart at the touch of the fork. You will (I promise) smell when it is done!