David Wheeler & Hannah Hart were my 4th great grandparents - and I've hit the same brick wall trying to figure out who Hannah's parents were. I'm showing a different birthdate for Hannah though: July 9, 1784 (in St George).
Per findagrave.com there are three Wheelers in North Parish Cemeteries, Saint George: David Sr. (Find A Grave Memorial # 29913935), Hannah (Find A Grave Memorial # 29913953) & their son David Jr (Find A Grave Memorial # 29913971 - he died young).
The info for Hannah shows a death date as Sep. 12, 1860 and the notation "Wife of David Wheeler, aged 76 years, 2 months, 3 days". (Note: I have not seen the stone myself)
When I run the numbers through an age calculator I come up with the July 9, 1784 birthdate. Stones have been wrong before though...
Where did you get the 30 Oct 1770 birthdate?
(I have a solid tie between David & Hannah, they are both mentioned in "The History of Thomaston, Rockland, and South Thomaston, Maine, from their first exploration, 1605; With Family Genealogies, Vol. 2" by Cyrus Eaton (1865) P 458-59 - and - "The Genealogical and Encyclopedic History of the Wheeler Family in America" Albert Gallatin Wheeler, Jr. American College of Genealogy Boston 1914, Page 886-87. (Published in 1914, this verifies - or is just a copy of - Eaton's work 49 years earlier.)