I haven't tried convicts personally. they are kind of plain looking for a reef tank. But my buddy had a 10-shoal in his store. They thrived in a 220g fowlr that received a full day's worth of natural sunlight, and therefore was overrun with live algae. 20 tangs total, 10,000 gph of flow, good params as he did not have to supplemental feed much- just no coral. Then his store went out of business in 2 years, he sold the convicts.
HTH