1. After floor tiller, before the tree.
2. Yes, but I think? TB2 is not waterproof.
3. If you size the bow back and soak the backing, no need to overcoat, just make sure you squeeze it down well. Use a smooth rod or beer bottle to help.
4. If you add more glue, it will add unneeded weight to the bow.
5. I have used wipe on poly to nice effect, over the backing as well.
If I have anything wrong, someone will correct me I hope.
Mike