Before I rush out to buy
Unfortunately the book is, I think, out of print; a decent Welsh library should have a copy in the reference section. The author, T. Ceiri Griffith, published the book himself in 2003 and it was printed at Y Lolfa press (I think Palas Print are booksellers rather than publishers).
It is indeed a treasure, and although it overlaps J.E.Griffith's book geographically in part, the author restricts his tables in general to the period from the mid-1600s to the present day; where his subjects are recorded earlier such a connection e.g. to J. E. Griffith's book is clearly marked. A few years earlier the author published a collection of Caernarvonshire wills.
Pinot