William STEWART - WHO WAS THE FATHER OF WILLIAM STEWART (1670-1716)?

I list the parents of WILLIAM STEWART (1670-1716) in my tree even though I actually do not know who the father of was.

At first I listed him as a son of
William STEWART (born ~1636– at Ballymoran, County Down, Ireland), William was named "on a Chancery Bill in 1676, in a case against the extensive Claneboye estate, a suit that lasted 20 years"..

I later found another tree at Ancestry.com that listed him as a son of
John STEWART , Baron of Physgill
B:1640 Wigtown Wigtownshire Scotland
D:13 Aug 1719 Wigtown, Wigtownshire, Scotland

Both men descend from:
John STEWART , Parson at Kirkmahoe, Dumfries-shire, Scotland
1529–1592
BIRTH 1529 • Kirkcudbright, Kirkcudbrightshire, Scotland
DEATH 19 AUGUST 1592 • Wigtownshire, Scotland

I hope that tests for SNP R-A8323 of some of the descendants of John STEWART (1529–1592) from whom I do NOT descend will prove whether or not I descend from him. Tests of the descendants of John's father or other members of his patriline may suffice, e.g., if no tested descendant of John STEWART (1529–1592) can be found.

I call the branch of the descendants of Sir John Stewart (died 1298).to which my match (783534) and I (143035) belong the "A8323 branch" because no reliable test for SNP R-A5021.exists, or can be created, See
https://www.yseq.net/product_reviews_info.php?products_id=62252&amp...

The results of our Big Y NGS test results are shown in the phylogenetic trees at
http://www.ytree.net/DisplayTree.php?blockID=3581&star=false and at
http://www.ytree.net/DisplayTree.php?blockID=86

The results of our Big Y NGS tests are also shown in the image at
https://www.ancestry.com/mediaui-viewer/collection/1030/tree/810478...

Only the results of my match (783534) are now displayed at
http://www.s781.org/HG38treeB.jpg