Hi Gadget,
It sounds good. Also, given this Cunningham, the ploughman married to Grace Logan, gave his age in the 1861 census as 50 which fits with a birthdate of 1811. They were staying in Drummore Cothouse.
In the census of 1841, there is a Cunningham Rae (age 25) working as a manservant for John Barclay at Drummore Farm. Could they be the same Cunningham Rae?
If so, it might mean the Cunningham Rae who died in 1903 was a real Kirkcudbright man. Born in Kirkcudbright?
Michael