Grace is in the eye of the beholder. Having paddled sit-and-switch almost exclusively for almost 45 years, primarily in skinny solo canoes, it is effortless for me, and is like riding a road bike on good asphalt compared to riding a mt. bike on a rough dirt road (with flat tires). This summer I paddled almost 400 miles in the Arctic (carbon bent shaft), and few years ago another 200+ miles in Alaska (wood straight shaft) all the while correction paddling in the stern of a slow tandem. Grace was not a term I contemplated. Conditions permitting, give me my 17'6" Voyager and my Zaveral, and a lot of miles ahead of me. Oh, and I enjoy that combination gunkholeing, twitching my butt to make whatever turn is necessary. Duffeks work in fast boats too.
And to those new to sit-and-switch, the switch is critical, and will very much determine both the efficiency and enjoyment of paddling. With a carbon bent shaft and good technique, paddling even one stroke per side can be effective. It can be effortless and automatic.