Ummm, what Tornado? Solo or 2 up? Crew weight? How much mast rotation?

My experience is with the modern rigged tornado, carbon rig and square top main sailing at ~430lbs. In Force 5 we were definitely pulling Cunningham. In Force 4 it was getting played. My general experience is you are faster if you are playing the cunni and leaving the mainsheet tight, or an appopriate combination of the two (in the big gusts add cunni and ease on mainsheet). This is the same on the F18 or Inter 20 or F20carbon, basically any modern boat.

If you are finding you have to foot off drastically and need more power then sure, don't pull downhaul. That really depends on the crew weight and base sail shape. If your sail is older it may not respond well to cunnigham. Dacron mains stretch a lot and don't respond the same either.