The death of Cynrig (JF-1) must have been important to the early writers of Wales. His death, and the reprisal from his 1st cousins, is recorded in a number of sources. [ See Maund : pp. 4, 6, 93, 94 ]
The figure below shows the sons of Cynrig (JF-1). Ninnian (JG-1) is the branch to my JONES family.
The sons of Rhys Sais (JG-4) are shown in the following figure. They are through the second son of Tudor Trevor (JC-1) and would have become the senior branch of the family tree. [ Oldest son had daughtered out.]