Sir Watkin played a significant role in the development of art in Wales, as an early patron of landscape painting there, which was to become the largest area of artistic activity in Wales. He brought both Richard Wilson and Paul Sandby to his seat at Wynnstay, Sandby staying six weeks in the summer of 1770, giving lessons to the family as well as painting, on his first visit to Wales. The next year Sandby returned and from 21 August to 4 September 1771 he and Sir Watkin toured through the mountains of northern Wales. From the sketches made on the tour Sandby published twelve aquatint "Views in North Wales" in 1776, and five of his "Views in Wales" of 1777. Matching sets from South Wales came from his tours there with Sir Joseph Banks, who commissioned the whole series. A more ambitious tour together, to Italy, was planned but cancelled after Sir Watkin's second marriage.