Are you putting her on the helm? If you can, let her/make her helm! The Tornado (and the F-18s) have quite high sheet loads, so it will probably be easier for you to trim sails.

The T need a little bit more wind before it flies a hull, but you are so light that it dont matter much. If you go for a Tornado, try to get a carbon mast as well. You are a little bit light to right it after a capsize, but the carbon mast makes it easier. You might also want to look into a custom mainsail, to match your weight.
I dont think the Tornado is more seaworthy than the F-18s. It is a bit longer and lighter, but the rig is also taller, so it evens out. The flat decks on the Tornado make it stop hard if you drive the bows under when coming down a wave..
If you are not going to race, perhaps you can find one of those prototype carbon Tornados buildt in the US?

If you do decide on a Tornado, there is a good Tornado mailing list with lots of US sailors at: http://groups.yahoo.com/group/TornadoCat/