Rich,
The answer to your question is yes, drop the jib and you have a class legal F17! The only problem that I see is if you weigh less than 215lbs the spin size will be too big. As it stands right now, the class rules are only written for the unirig,
http://nacraclass.com/northamerica/rules_F17.htm. If you weigh more than 215lbs, the chute will be the right one.
There is a saving grace here. I'm sure there are a few guys who would let you borrow a class unirig chute for some races. If you are planning on joining us at the NAs, drop me an email and you can gladly use one of mine. The sloop rig comes with the larger chute because there is a bit more weight (crew) to pull around!
Nacra Europe is involved in the promotion and development of the F104 class which is sloop w/crew only. Over there, there are quite a few manufacturers with boats that rate 1.04.
Hope this sheds some light,
Bob <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />