"Fascinating, Captain" -- thank you for sharing that link, cousin. I'm also a descendant, and have been contributing to Thomas's profile. On the one hand (no pun intended), the man's signature would seem to deserve some kind of particular recognition; by WikiTree convention, however, I'm not sure it takes precedence over other spellings -- except for a demonstrable surname-at-birth.
In the general debate, the signature does influence me to lean to a spelling that at least shows a double "e" (rather than to "Dibble"). One of the two profiles now awaiting a merge is Deeble-1, and I think I'd now prefer we retain that version of the name. The signature would seem to at least suggest that Thomas grew up hearing the name pronounced more nearly to that than to Dibble.