......would it be possible to change the shoal version to a deep draft version?
There was a guy in our yacht club who changed his fin keel to a wing keel. He would have consulted with the designer or a naval architect before he started. He did the work himself with friends helping. He cut a 2 or 3 feet off the keel, made a mold for the wing and casted it with the lead he removed, plus some more. He drilled and lagged several bolts into the fin and bolted the wing on. Major job, but do-able.