It sounds like your hull may be too far gone for a deck repair to "fix it for good." The fact that the whole hull toed in makes me conclude that the sides of the hull have been compromised as well That said, the most structurally sound deck fix I've seen is to remove the top skin and all the delam/previous delam fix crap until you have solid stuff to which you can bond. Then go back with balsa and resin before reglassing the top. I've seen such a repair hold up to years of heavy abuse, but it was not as large an area as yours sounds.

I know you said it's not an option, but I highly recommend replacement. If you've got the time to kill, you may be able to get some more use out of the hull, but I don't think you can come close to "for good".

Just an opinion.