For what it is worth I have put together a simplified family tree for the Williams family of Dorset & their descendants. It links together the "main" family of Williams of Herringston with the "cadet" families of Williams of Bridehead and Williams of Rushden Hall. The primary sources have been various editions of Burke's Landed Gentry plus Fox-Davies' Armorial Families and some census details. It can be viewed at;
http://williams-herringston.50webs.com/Williams%20of%20Herri...If they are any errors or omissions please do drop me a line.
Yours aye
Stephen