Choose a minimal expansion polyeurathane spray foam, it will produce results closer (not identical) to your 3-D's origional foam than maximum (triple) expansion foam. Do not wrap since air is necessary for the foam to cure. Fill deer in place until the foam begins to run out, then stop, cure, and repeat. When the core is filled (okay, over-filled and looks all misshapen), trim with a serrated bread knife. This will give you about 1/3 the origional shooting time you had with the origional and is really only good to do once.
Also, you may find the foam adhering to certian arrows. I shoot woodies and have very little trouble with this but if your shooting alluminum or carbons at high velocity, well...
Good luck!
-Brett