A number of general sources of Coutts family history and Heraldry are attached. Similarly infomation is available under Heraldry and the Links section as a very detailed list of general and specific resources.
The most available information relates to the Montrose Coutts both before the Bank and after the banking sons left for London. I have chosen not to keep a lot of detail here in this regard as so much is available elsewhere.
The free resources on archive.org are an excellent source.
GENEALOGICAL MEMOIRS the FAMILIES OF COLT AND COUTTS,
REV. CHARLES ROGERS, 1860, Families of Colt and Coutts