How exactly did you "rebuild the stringers and transom" without doing any glass work yet?
It is not hard, but it is not easy either. I have several books and videos on the topic. I would go get something along those lines. The west system book at west marine is not bad and is cheap ( <$10).
http://www.fiberglass-repair.com/ has a pretty good DVD that will give you the basics on how to glass and it is nice to see him actuall do it than just read it in a book. There are also a bunch of good website message boards that can help you along the way, probably much better than this one, ie. hull truth, classicmako, etc...
You should wear one of those tyvec suits and have a good respirator. This schit is nasty.
Filling the whole hull with the foam is a good idea. You do have to leave drainage, though. If you use the two part expandable foam, do it before you put the floor back on, otherwise you stand a higher chance of f-ing up the shape of the hull. Don't get me wrong, you can do it with the floor on, but it will come out better if you do the foam first.
What are you going to use for a core for the floor? That is a question I am debating now myself....
There is so much more to say, but I guess I will leave it at that.
_Z_
Good luck.